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Note: This page contains sample records for the topic "radio frequency identification" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

SECURING RADIO FREQUENCY IDENTIFICATION (RFID)  

E-Print Network [OSTI]

business process for an organization; as a result, the security risks for RFID systems and the controls for an organization; as a result, the security risks for RFID systems and the controls available to address themMay 2007 SECURING RADIO FREQUENCY IDENTIFICATION (RFID) SYSTEMS SECURING RADIO FREQUENCY

2

Radio Frequency Identification : regulating information privacy protection  

E-Print Network [OSTI]

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

Laufer, Deanna (Deanna Raquel)

2007-01-01T23:59:59.000Z

3

Security approaches for Radio Frequency Identification systems  

E-Print Network [OSTI]

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

Foley, Joseph Timothy, 1976-

2007-01-01T23:59:59.000Z

4

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

E-Print Network [OSTI]

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

Shah, Ronak R

2005-01-01T23:59:59.000Z

5

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

E-Print Network [OSTI]

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

Shen, Howard H. (Howard Hao)

2006-01-01T23:59:59.000Z

6

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

E-Print Network [OSTI]

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

Fonseca, Herbert Moreti, 1973-

2004-01-01T23:59:59.000Z

7

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

E-Print Network [OSTI]

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

Chen, Yan (Yan Henry), 1976-

2005-01-01T23:59:59.000Z

8

Radio-frequency identification could help reduce the spread of plant pathogens  

E-Print Network [OSTI]

frequency identification could help reduce the spread ofeconomic losses. It also helps control the Plant Protection

Luvisi, Andrea; Panattoni, Alessandra; Triolo, Enrico

2012-01-01T23:59:59.000Z

9

Radio frequency detection assembly and method for detecting radio frequencies  

DOE Patents [OSTI]

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

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

2010-03-16T23:59:59.000Z

10

RADIO FREQUENCY IDENTIFICATION DEVICES: EFFECTIVENESS IN IMPROVING SAFEGUARDS AT GAS-CENTRIFUGE URANIUM-ENRICHMENT PLANTS.  

SciTech Connect (OSTI)

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.

JOE,J.

2007-07-08T23:59:59.000Z

11

Stabilized radio frequency quadrupole  

DOE Patents [OSTI]

Disclosed is a long-vane stabilized radio frequency resonator for accelerating charged particles and including means defining a radio frequency resonator cavity, a plurality of long vanes mounted in the defining means for dividing the cavity into sections, and means interconnecting opposing ones of the plurality of vanes for stabilizing the resonator. 5 figs.

Lancaster, H.D.; Fugitt, J.A.; Howard, D.R.

1984-12-25T23:59:59.000Z

12

Demonstration (DEMO) of Radio Frequency Identification (RFID) system for tracking and monitoring of nuclear materials.  

SciTech Connect (OSTI)

The US Department of Energy (DOE) [Environmental Management (EM), Office of Packaging and Transportation (EM-45)] Packaging Certification Program (PCP) has developed a radiofrequency identification (RFID) tracking and monitoring system for the management of nuclear materials packages during storage and transportation. The system, developed by the PCP team at Argonne National Laboratory, involves hardware modification, application software development, secured database and web server development, and irradiation experiments. In April 2008, Argonne tested key features of the RFID tracking and monitoring system in a weeklong, 1700 mile (2736 km) demonstration employing 14 empty type B fissile material drums of three designs (models 9975, 9977 and ES-3100) that have been certified for shipment by the DOE and the US Nuclear Regulatory Commission. The demonstration successfully integrated global positioning system (GPS) technology for vehicle tracking, satellite/cellular (general packet radio service, or GPRS) technologies for wireless communication, and active RFID tags with multiple sensors (seal integrity, shock, temperature, humidity and battery status) on drums. In addition, the demonstration integrated geographic information system (GIS) technology with automatic alarm notifications of incidents and generated buffer zone reports for emergency response and management of staged incidents. The demonstration was sponsored by EM and the US National Nuclear Security Administration, with the participation of Argonne, Savannah River and Oak Ridge National Laboratories. Over 50 authorised stakeholders across the country observed the demonstration via secured Internet access. The DOE PCP and national laboratories are working on several RFID system implementation projects at selected DOE sites, as well as continuing device and systems development and widening applications beyond DOE sites and possibly beyond nuclear materials to include other radioactive materials.

Tsai, H. C.; Chen, K.; Liu, Y. Y.; Shuler, J. (Decision and Information Sciences); (USDOE)

2010-01-01T23:59:59.000Z

13

Stabilized radio-frequency quadrupole  

DOE Patents [OSTI]

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

Lancaster, H.D.; Fugitt, J.A.; Howard, D.R.

1982-09-29T23:59:59.000Z

14

"To appear in Bureau, S., Prabhu, B. S., & Gadh, R. 2008. Radio Frequency Identification: Beyond the Myths. A case for Health Care. Paper presented at the Academy of Management, 8-13 aot, Anaheim, Ca, USA"  

E-Print Network [OSTI]

15923 1 "To appear in Bureau, S., Prabhu, B. S., & Gadh, R. 2008. Radio Frequency Identification, School of Engineering University of California, Los Angeles & R. Gadh Professor, School of Engineering

California at Los Angeles, University of

15

Rajit Gadh and B.S. Prabhu, Radio Frequency Identification (RFID) for the assistance of Katrina related disaster mortuary operations, IEEE Signal Processing, expected to appear March 2006, based on invitation to write short article.  

E-Print Network [OSTI]

Rajit Gadh and B.S. Prabhu, Radio Frequency Identification (RFID) for the assistance of Katrina of Katrina Hurricane Victims Rajit Gadh and B.S. Prabhu Recently news.com reported that the U.S. Disaster

California at Los Angeles, University of

16

Microwave and Radio Frequency Workshop  

Broader source: Energy.gov [DOE]

At the Microwave and Radio Frequency Workshop (held in Long Beach, CA, on July 25, 2012), academic and industry experts discussed the existing and emerging electrotechnologies – such as microwave ...

17

Intelligent Radio Frequency (RF) Monitoring  

E-Print Network [OSTI]

? Intelligent Radio Frequency (RF) Monitoring ? 2009 Armstrong International, Inc. www.armstronginternational.com 2 ?Expect many enjoyable experiences!? David M. Armstrong Present Process Challenges ? Identifying a failure ? Procedure.... Armstrong Steam Trap Challenges ? Identifying a failure ? Manpower ? Location ? Magnitude of failure ? Energy loss ? Loss of heat transfer ? Justification for repair ? ?Speed of Implementation? ? Environmental concerns Manpower Location 4...

Kimbrough, B.

18

Medium-Sized Mammals around a Radioactive Liquid Waste Lagoon at Los Alamos National Laboratory: Uptake of Contaminants and Evaluation of Radio-Frequency Identification Technology  

SciTech Connect (OSTI)

Use of a radioactive liquid waste lagoon by medium-sized mammals and levels of tritium, other selected radionuclides, and metals in biological tissues of the animals were documented at Technical Area 53 (TA-53) of Los Alamos National Laboratory during 1997 and 1998. Rock squirrel (Spermophilus variegates), raccoon (Procyon lotor), striped skunk (Mephitis mephitis), and bobcat (Lynx rufus) were captured at TA-53 and at a control site on the Santa Fe National Forest. Captured animals were anesthetized and marked with radio-frequency identification (RFD) tags and/or ear tags. We collected urine and hair samples for tritium and metals (aluminum, antimony, arsenic, barium, beryllium, cadmium, chromium, copper, lead, mercury, nickel, selenium, silver, and thallium) analyses, respectively. In addition, muscle and bone samples from two rock squirrels collected from each of TA-53, perimeter, and regional background sites were tested for tritium, {sup 137}Cs, {sup 90}Sr, {sup 238}Pu, {sup 239,240}Pu, {sup 241}Am, and total uranium. Animals at TA-53 were monitored entering and leaving the lagoon area using a RFID monitor to read identification numbers from the RFID tags of marked animals and a separate camera system to photograph all animals passing through the monitor. Cottontail rabbit (Sylvilagus spp.), rock squirrel, and raccoon were the species most frequently photographed going through the RFID monitor. Less than half of all marked animals in the lagoon area were detected using the lagoon. Male and female rock squirrels from the lagoon area had significantly higher tritium concentrations compared to rock squirrels from the control area. Metals tested were not significantly higher in rock squirrels from TA-53, although there was a trend toward increased levels of lead in some individuals at TA-53. Muscle and bone samples from squirrels in the lagoon area appeared to have higher levels of tritium, total uranium, and {sup 137}Cs than samples collected from perimeter and background locations. However, the committed effective dose equivalent estimated from the potential human consumption of the muscle and bone tissue from these rock squirrels did not suggest any human health risk. Indirect routes of tritium uptake, possibly through consumption of vegetation, are important for animals in the lagoon area.

Leslie A. Hansen; Phil R. Fresquez; Rhonda J. Robinson; John D. Huchton; Teralene S. Foxx

1999-11-01T23:59:59.000Z

19

High power radio frequency attenuation device  

DOE Patents [OSTI]

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

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

1984-01-01T23:59:59.000Z

20

E-Print Network 3.0 - applied radio frequency Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Doctor Summary: schemes to optimally use the radio frequency and power resource in cognitive radio networks. The proposed... radio frequency intelligently according to the radio...

Note: This page contains sample records for the topic "radio frequency identification" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

A Framework for Radio Frequency Spectrum Measurement and Analysis  

E-Print Network [OSTI]

A Framework for Radio Frequency Spectrum Measurement and Analysis V. Rory Petty ITTC-FY2008-TR allocation and the burgeoning problem of spectrum scarcity have prompted an examination of how the radio frequency spectrum is utilized. The radio frequency spectrum is an important national resource that impacts

Kansas, University of

22

Radio frequency (RF) heated supersonic flow laboratory  

SciTech Connect (OSTI)

A unique supersonic flow apparatus which employs an inductively-coupled, radio frequency (RF) torch to supply high enthalpy source gas to the nozzle inlet is described. The main features of this system are the plasma tube, a cooled nozzle assembly, and a combustion/expansion chamber with a heat exchanger. A description of these components with current test data is presented. In addition, a discussion of anticipated experiments utilizing this system is included.

Wantuck, P.; Watanabe, H.

1990-01-01T23:59:59.000Z

23

Two Phase Spectrum Sharing for Frequency-Agile Radio Networks  

E-Print Network [OSTI]

1 Two Phase Spectrum Sharing for Frequency-Agile Radio Networks Zhenhua Feng and Yaling Yang of modern radios. We solve a joint spectrum sharing and end-to-end rate control problems for general technologies (e.g. software defined radio and cognitive radios) enable more flexible spectrum access through

Ha, Dong S.

24

E4.18 Radio Frequency Electronics Copyright 2006 Dr Stepan Lucyszyn Frequency Spectrum  

E-Print Network [OSTI]

Applications Phased-array radar Electronic warfare (e.g. Electronic Surveillance Measures, ECM, ECCM, decoysE4.18 Radio Frequency Electronics Copyright © 2006 Dr Stepan Lucyszyn Frequency Spectrum and Applications #12;E4.18 Radio Frequency Electronics Copyright © 2006 Dr Stepan Lucyszyn #12;E4.18 Radio

Papavassiliou, Christos

25

An improved integrally formed radio frequency quadrupole  

DOE Patents [OSTI]

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.

Abbott, S.R.

1987-10-05T23:59:59.000Z

26

Circuits and passive components for radio-frequency power conversion  

E-Print Network [OSTI]

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

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

2010-01-01T23:59:59.000Z

27

Trirotron: triode rotating beam radio frequency amplifier  

DOE Patents [OSTI]

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

Lebacqz, Jean V. (Stanford, CA)

1980-01-01T23:59:59.000Z

28

Grain Growth in Niobium for Superconducting Radio Frequency Cavities  

E-Print Network [OSTI]

GRAIN GROWTH IN NIOBIUM FOR SUPERCONDUCTING RADIO FREQUENCY CAVITIES Major: Mechanical Engineering April 2009 Submitted to the Office of Undergraduate Research Texas A&M University in partial fulfillment... of the requirements for the designation as UNDERGRADUATE RESEARCH SCHOLAR A Senior Scholars Thesis by Joshua A. Vernon GRAIN GROWTH IN NIOBIUM FOR SUPERCONDUCTING RADIO FREQUENCY CAVITIES Approved by: Research Advisor: K. T. Hartwig...

Vernon, Joshua A.

2009-06-09T23:59:59.000Z

29

Radio Frequency Id and Privacy with Information Goods Nathan Gooda1  

E-Print Network [OSTI]

of Computing] General Terms Security, Legal Aspects. Keywords RFID, privacy, information goods, law, policy. 1. NORMS AND LAW This paper examines the privacy impacts of using radio frequency identification (RFID privacy. Put simply, in the RFID-enabled world, anyone with an RFID reader can potentially discover

Wagner, David

30

Method and apparatus for radio frequency ceramic sintering  

DOE Patents [OSTI]

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

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

1993-11-30T23:59:59.000Z

31

Method and apparatus for radio frequency ceramic sintering  

DOE Patents [OSTI]

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.

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

1993-01-01T23:59:59.000Z

32

High-power radio-frequency attenuation device  

DOE Patents [OSTI]

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

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

1981-12-30T23:59:59.000Z

33

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

SciTech Connect (OSTI)

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

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

2014-02-15T23:59:59.000Z

34

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

SciTech Connect (OSTI)

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.

Dowla, F

2007-03-14T23:59:59.000Z

35

Predicting low-frequency radio fluxes of known extrasolar planets  

E-Print Network [OSTI]

Context. Close-in giant extrasolar planets (''Hot Jupiters'') are believed to be strong emitters in the decametric radio range. Aims. We present the expected characteristics of the low-frequency magnetospheric radio emission of all currently known extrasolar planets, including the maximum emission frequency and the expected radio flux. We also discuss the escape of exoplanetary radio emission from the vicinity of its source, which imposes additional constraints on detectability. Methods. We compare the different predictions obtained with all four existing analytical models for all currently known exoplanets. We also take care to use realistic values for all input parameters. Results. The four different models for planetary radio emission lead to very different results. The largest fluxes are found for the magnetic energy model, followed by the CME model and the kinetic energy model (for which our results are found to be much less optimistic than those of previous studies). The unipolar interaction model does ...

Grießmeier, J -M; Spreeuw, H

2008-01-01T23:59:59.000Z

36

Predicting low-frequency radio fluxes of known extrasolar planets  

E-Print Network [OSTI]

Context. Close-in giant extrasolar planets (''Hot Jupiters'') are believed to be strong emitters in the decametric radio range. Aims. We present the expected characteristics of the low-frequency magnetospheric radio emission of all currently known extrasolar planets, including the maximum emission frequency and the expected radio flux. We also discuss the escape of exoplanetary radio emission from the vicinity of its source, which imposes additional constraints on detectability. Methods. We compare the different predictions obtained with all four existing analytical models for all currently known exoplanets. We also take care to use realistic values for all input parameters. Results. The four different models for planetary radio emission lead to very different results. The largest fluxes are found for the magnetic energy model, followed by the CME model and the kinetic energy model (for which our results are found to be much less optimistic than those of previous studies). The unipolar interaction model does not predict any observable emission for the present exoplanet census. We also give estimates for the planetary magnetic dipole moment of all currently known extrasolar planets, which will be useful for other studies. Conclusions. Our results show that observations of exoplanetary radio emission are feasible, but that the number of promising targets is not very high. The catalog of targets will be particularly useful for current and future radio observation campaigns (e.g. with the VLA, GMRT, UTR-2 and with LOFAR).

J. -M. Grießmeier; P. Zarka; H. Spreeuw

2008-06-02T23:59:59.000Z

37

Low frequency radio spectrum and spectral turnover of LS 5039  

E-Print Network [OSTI]

LS 5039, a possible black hole x-ray binary, was recently observed with Giant Meterwave Radio Telescope. The observed spectrum presented here shows that the spectrum is inverted at the low frequency. When combined with the archival data with orbital phase similar to the present observations, it shows a clear indication of a spectral turnover. The combined data are fitted with a broken power-law and the break frequency signifies a possible spectral turnover of the spectrum around 964 MHz. Truly simultaneous observations in radio wavelength covering a wide range of frequencies are required to fix the spectrum and the spectral turn over which will play a crucial role in developing a deeper understanding of the radio emitting jet in LS 5039.

Sagar Godambe; Subir Bhattacharyya; Nilay Bhatt; Manojendu Choudhury

2008-07-15T23:59:59.000Z

38

Faraday Accelerator with Radio-frequency Assisted Discharge (FARAD)  

E-Print Network [OSTI]

rights reserved. #12;Abstract A new electrodeless accelerator concept, called Faraday Accelerator with Radio-frequency Assisted Discharge (FARAD), that relies on an RF-assisted discharge to produce a plasma, an applied magnetic field to guide the plasma into the acceleration region, and an induced current sheet

Choueiri, Edgar

39

Power Supplies and Radio Frequency Department at Culham  

E-Print Network [OSTI]

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

40

Localized radio frequency communication using asynchronous transfer mode protocol  

DOE Patents [OSTI]

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.

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

2007-08-14T23:59:59.000Z

Note: This page contains sample records for the topic "radio frequency identification" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

LOFAR: A new radio telescope for low frequency radio observations: Science and project status  

E-Print Network [OSTI]

LOFAR, the Low Frequency Array, is a large radio telescope consisting about 100 soccer field sized antenna stations spread over a region of 400 km in diameter. It will operate in the frequency range from ~10 to 240 MHz, with a resolution at 240 MHz of better than an arcsecond. Its superb sensitivity will allow for a broad range of astrophysical studies. In this contribution we first discuss four major areas of astrophysical research in which LOFAR will undoubtedly make important contributions: reionisation, distant galaxies and AGNs, transient radio sources and cosmic rays. Subsequently, we will discuss the technical concept of the instrument and the status of the LOFAR project

H. Rottgering; A. G. de Bruyn; R. P. Fender; J. Kuijpers; M. P. van Haarlem; M. Johnston-Hollitt; G. K Miley

2003-07-11T23:59:59.000Z

42

Exploring the magnetized cosmic web through low frequency radio emission  

E-Print Network [OSTI]

Recent improvements in the capabilities of low frequency radio telescopes provide a unique opportunity to study thermal and non-thermal properties of the cosmic web. We argue that the diffuse, polarized emission from giant radio relics traces structure formation shock waves and illuminates the large-scale magnetic field. To show this, we model the population of shock-accelerated relativistic electrons in high-resolution cosmological simulations of galaxy clusters and calculate the resulting radio synchrotron emission. We find that individual shock waves correspond to localized peaks in the radio surface brightness map which enables us to measure Mach numbers for these shocks. We show that the luminosities and number counts of the relics strongly depend on the magnetic field properties, the cluster mass and dynamical state. By suitably combining different cluster data, including Faraday rotation measures, we are able to constrain some macroscopic parameters of the plasma at the structure formation shocks, such as models of turbulence. We also predict upper limits for the properties of the warm-hot intergalactic medium, such as its temperature and density. We predict that the current generation of radio telescopes (LOFAR, GMRT, MWA, LWA) have the potential to discover a substantially larger sample of radio relics, with multiple relics expected for each violently merging cluster. Future experiments (SKA) should enable us to further probe the macroscopic parameters of plasma physics in clusters.

N. Battaglia; C. Pfrommer; J. L. Sievers; J. R. Bond; T. A. Ensslin

2009-08-07T23:59:59.000Z

43

Radio frequency communication system utilizing radiating transmission lines  

DOE Patents [OSTI]

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

Struven, Warren C. (San Carlos, CA)

1984-01-01T23:59:59.000Z

44

Final report: In situ radio frequency heating demonstration  

SciTech Connect (OSTI)

A field demonstration of in situ radio frequency heating was performed at the Savannah River Site (SRS) as part of the US Department of Energy-Office of Technology Development`s Integrated Demonstration. The objective of the demonstration was to investigate the effectiveness of in situ radio frequency (RF) heating as an enhancement to vacuum extraction of residual solvents (primarily trichloroethylene and perchloroethylene) held in vadose zone clay deposits. Conventional soil vacuum extraction techniques are mass transfer limited because of the low permeabilities of the clays. By selectively heating the clays to temperatures at or above 100{degrees}C, the release or transport of the solvent vapors will be enhanced as a result of several factors including an increase in the contaminant vapor pressure and diffusivity and an increase in the effective permeability of the formation with the release of water vapor.

Jarosch, T.R.; Beleski, R.J.; Faust, D.

1994-01-05T23:59:59.000Z

45

Synchrotron Radiation at Radio Frequencies from Cosmic Ray Air Showers  

E-Print Network [OSTI]

We review some of the properties of extensive cosmic ray air showers and describe a simple model of the radio-frequency radiation generated by shower electrons and positrons as they bend in the Earth's magnetic field. We perform simulations by calculating the trajectory and radiation of a few thousand charged shower particles. The results are then transformed to predict the strength and polarization of the electromagnetic radiation emitted by the whole shower.

Denis A. Suprun; Peter W. Gorham; Jonathan L. Rosner

2003-06-06T23:59:59.000Z

46

Synchrotron Radiation at Radio Frequencies from Cosmic Ray Air Showers  

E-Print Network [OSTI]

We review some of the properties of extensive cosmic ray air showers and describe a simple model of the radio-frequency radiation generated by shower electrons and positrons as they bend in the Earth's magnetic field. We perform simulations by calculating the trajectory and radiation of a few thousand charged shower particles. The results are then transformed to predict the strength and polarization of the electromagnetic radiation emitted by the whole shower.

Suprun, D A; Rosner, Jonathan L; Suprun, Denis A.; Gorham, Peter W.; Rosner, Jonathan L.

2003-01-01T23:59:59.000Z

47

Longitudinal capture in the radio-frequency-quadrupole structure  

SciTech Connect (OSTI)

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.

Inagaki, S.

1980-03-01T23:59:59.000Z

48

Terahertz bandwidth integrated radio frequency spectrum analyzer via nonlinear optics  

E-Print Network [OSTI]

We report an integrated all-optical radio frequency spectrum analyzer based on a ~ 4cm long doped silica glass waveguide, with a bandwidth greater than 2.5 THz. We use this device to characterize the intensity power spectrum of ultrahigh repetition rate mode-locked lasers at repetition rates up to 400 GHz, and observe dynamic noise related behavior not observable with other techniques.

Ferrera, Marcello; Pasquazi, Alessia; Peccianti, Marco; Clerici, Matteo; Caspani, Lucia; Chu, Sai T; Little, Brent E; Morandotti, Roberto; Moss, David J

2014-01-01T23:59:59.000Z

49

Physical properties of conventional explosives deduced from radio frequency emissions  

SciTech Connect (OSTI)

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

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

2008-01-01T23:59:59.000Z

50

Ross Ice Shelf in situ radio-frequency ice attenuation  

E-Print Network [OSTI]

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

Taylor Barrella; Steven Barwick; David Saltzberg

2012-05-01T23:59:59.000Z

51

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

E-Print Network [OSTI]

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

Glebov, Leon

52

Frequency-based structural damage identification and dynamic system characterisation   

E-Print Network [OSTI]

This thesis studies structural dynamic system identification in a frequency-based framework. The basic consideration stems from the fact that frequencies may generally be measured with higher accuracy than other pertinent ...

Mao, Lei

2012-11-29T23:59:59.000Z

53

The radio-frequency impedance of individual intrinsic Josephson junctions  

SciTech Connect (OSTI)

We have measured the response of an array of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} intrinsic Josephson junctions to irradiation at 3 GHz. By measuring the dependence of the switching current upon the radio-frequency current for five of the junctions in the array we show quantitatively that the junctions have identical impedances at 3 GHz, this impedance being given by the inverse of the slope of the current-voltage characteristics.

Leiner, Johannes; Saleem, Sajid; Fenton, J. C.; Warburton, P. A. [London Centre for Nanotechnology, University College London, 17-19 Gordon Street, London WC1H 0AH (United Kingdom); Yamamoto, Takashi; Kadowaki, Kazuo [Institute of Materials Science, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan)

2009-12-21T23:59:59.000Z

54

Hermetic aluminum radio frequency interconnection and method for making  

DOE Patents [OSTI]

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

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

2000-01-01T23:59:59.000Z

55

CENSORS: A Combined EIS-NVSS Survey Of Radio Sources. I. Sample definition, radio data and optical identifications  

E-Print Network [OSTI]

A new sample of radio sources, with the designated name CENSORS (A Combined EIS-NVSS Survey Of Radio Sources), has been defined by combining the NRAO VLA Sky Survey (NVSS) at 1.4 GHz with the ESO Imaging Survey (EIS) Patch D, a 3 by 2 degree region of sky centred at 09 51 36.0, -21 00 00 (J2000). New radio observations of 199 NVSS radio sources with NVSS flux densities S(1.4GHz) > 7.8mJy are presented, and compared with the EIS I-band imaging observations which reach a depth of I~23; optical identifications are obtained for over two-thirds of the ~150 confirmed radio sources within the EIS field. The radio sources have a median linear size of 6 arcseconds, consistent with the trend for lower flux density radio sources to be less extended. Other radio source properties, such as the lobe flux density ratios, are consistent with those of brighter radio source samples. From the optical information, 30-40% of the sources are expected to lie at redshifts z >~ 1.5. One of the key goals of this survey is to accurately determine the high redshift evolution of the radio luminosity function. These radio sources are at the ideal flux density level to achieve this goal; at redshifts z~2 they have luminosities which are around the break of the luminosity function and so provide a much more accurate census of the radio source population at those redshifts than the existing studies of extreme, high radio power sources. Other survey goals include investigating the dual--population unification schemes for radio sources, studying the radio luminosity dependence of the evolution of radio source environments, and understanding the radio power dependence of the K-z relation for radio galaxies.

P. N. Best; J. N. Arts; H. J. A. Rottgering; R. Rengelink; M. H. Brookes; J. Wall

2003-08-22T23:59:59.000Z

56

E-Print Network 3.0 - atmospheric pressure radio-frequency Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

amorphous powder during the polymerization of ethylene in a radio-frequency dis- charge," J. Appl. Polymer... of Monomer Pressure Evolution in an Inductively Coupled ... Source:...

57

Radio-frequency probes of Antarctic ice at South Pole  

E-Print Network [OSTI]

System Sciences O p e n A cce ss Discussions Radio-frequency probes of Antarctic ice at South Pole D. Besson1 and I. Kravchenko2 1University of Kansas, Department of Physics and Astronomy, Lawrence, KS 66045-7582, USA 2University of Nebraska – Lincoln... to successive waveforms. Each 0.5 meter division horizontally corresponds to approximately 5 ns. -20 -10 0 10 20 Rx v ol ta ge ( V, a ft er s ca li ng ; of fs e Time (ns, relative) 6 us echo (Vx1) 9.6 us echo (Vx1.3) 13.9 us echo (Vx3.5) 17.2 us echo (Vx10...

Besson, David Zeke; Kravchenko, I.

2013-05-16T23:59:59.000Z

58

Ultrafast electron diffraction with radio-frequency compressed electron pulses  

SciTech Connect (OSTI)

We report on the complete characterization of time resolution in an ultrafast electron diffraction (UED) instrument based on radio-frequency electron pulse compression. The temporal impulse response function of the instrument was determined directly in pump-probe geometry by performing electron-laser pulse cross-correlation measurements using the ponderomotive interaction. With optimal settings, a stable impulse response of 334{+-}10 fs was measured at a bunch charge of 0.1 pC (6.24 Multiplication-Sign 10{sup 5} electrons/pulse); a dramatic improvement compared to performance without pulse compression. Phase stability currently limits the impulse response of the UED diffractometer to the range of 334-500 fs, for bunch charges ranging between 0.1 and 0.6 pC.

Chatelain, Robert P.; Morrison, Vance R.; Godbout, Chris; Siwick, Bradley J. [Departments of Physics and Chemistry, Center for the Physics of Materials, McGill University, Montreal (Canada)

2012-08-20T23:59:59.000Z

59

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

SciTech Connect (OSTI)

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.

Kim, Dan Bee [Division of Physical Metrology, Korea Research Institute of Standards and Science, 209 Gajeongno, Yuseong-gu, Daejeon 305-340 (Korea, Republic of); Jung, H.; Gweon, B.; Rhee, J. K.; Choe, W. [Department of Physics, Korea Advanced Institute of Science and Technology, 335 Gwahangno, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Moon, S. Y. [LG Electronics Advanced Research Institute, 16 Woomyeon-Dong, Seocho-Gu, Seoul 137-724 (Korea, Republic of)

2011-04-15T23:59:59.000Z

60

Single-cycle radio-frequency pulse generation by an optoelectronic  

E-Print Network [OSTI]

Single-cycle radio-frequency pulse generation by an optoelectronic oscillator Etgar C. Levy,1-locking of an optoelectronic oscillator which generates a single-cycle radio-frequency pulse train. The measured pulse to pulse by a passive mode-locked oscillator. The passive mode-locked optoelectronic oscillator is important

Horowitz, Moshe

Note: This page contains sample records for the topic "radio frequency identification" from the National Library of EnergyBeta (NLEBeta).
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61

Large area radio frequency plasma for microelectronics processing Z. Yu and D. Shaw  

E-Print Network [OSTI]

focus on wide area plasma uniformity and undesired antenna window erosion caused by the plasma. OurLarge area radio frequency plasma for microelectronics processing Z. Yu and D. Shaw Colorado State November 1994 Radio-frequency rf inductively coupled planar plasma ICP provides a better way to generate

Collins, George J.

62

Detectability of Radio Frequency Interference due to Spread Spectrum Communication Signals using the  

E-Print Network [OSTI]

Detectability of Radio Frequency Interference due to Spread Spectrum Communication Signals using-- Analysis of detectability of the kurtosis algorithm for pulsed-sinusoidal Radio Frequency Interference (RFI) has already been performed in detail. The detectability for wide- band spread-spectrum RFI

Ruf, Christopher

63

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

SciTech Connect (OSTI)

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.

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

2014-11-07T23:59:59.000Z

64

Spectrum hole identification and exploitation in cognitive radio networks.  

E-Print Network [OSTI]

??Cognitive radio networks are envisaged as the solution for effective spectrum management for the future communications. In a cognitive radio network, the unlicensed users are… (more)

Vamsi Krishna Tumuluru.

2011-01-01T23:59:59.000Z

65

The Identification of EGRET Sources with Flat-Spectrum Radio Sources  

E-Print Network [OSTI]

We present a method to assess the reliability of the identification of EGRET sources with extragalactic radio sources. We verify that EGRET is detecting the blazar class of AGN. However, many published identifications are found to be questionable. We provide a table of 42 blazars which we expect to be robust identifications of EGRET sources. This includes one previously unidentified EGRET source, the lensed AGN PKS 1830-210 near the direction of the Galactic center. We provide the best available positions for 16 more radio sources which are also potential identifications for previously unidentified EGRET sources. All high Galactic latitude EGRET sources (b>3 degrees) which demonstrate significant variability can be identified with flat spectrum radio sources. This suggests that EGRET is not detecting any type of AGN other than blazars. This identification method has been used to establish with 99.998% confidence that the peak gamma-ray flux of a blazar is correlated with its average 5 GHz radio flux. An even better correlation is seen between gamma-ray flux and the 2.29 GHz flux density measured with VLBI at the base of the radio jet. Also, using high confidence identifications, we find that the radio sources identified with EGRET sources have larger correlated VLBI flux densities than the parent population of flat radio spectrum sources.

J. R. Mattox; J. Schachter; L. Molnar; R. C. Hartman; A. R. Patnaik

1996-12-18T23:59:59.000Z

66

Energy Saving Glass Lamination via Selective Radio Frequency Heating  

SciTech Connect (OSTI)

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.

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

2009-11-11T23:59:59.000Z

67

Radio-frequency quadrupole vane-tip geometries  

SciTech Connect (OSTI)

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

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

1983-01-01T23:59:59.000Z

68

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

E-Print Network [OSTI]

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

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

2014-09-30T23:59:59.000Z

69

Energy Saving Glass Lamination via Selective Radio-Frequency Heating  

SciTech Connect (OSTI)

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

Shulman, Holly S.; Allan, Shawn M.

2009-11-11T23:59:59.000Z

70

Scattering of radio frequency waves by blobs in tokamak plasmas  

SciTech Connect (OSTI)

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

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

2013-05-15T23:59:59.000Z

71

Diagnostic technique for measuring plasma parameters near surfaces in radio frequency discharges  

E-Print Network [OSTI]

Diagnostic technique for measuring plasma parameters near surfaces in radio frequency discharges September 1998 A plasma diagnostic technique for measuring the electron density, electron temperature the plasma parameters. The technique is demonstrated by implementing the diagnostic in a computer model

Kushner, Mark

72

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

E-Print Network [OSTI]

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

Ellingson, Steven W.

73

E-Print Network 3.0 - argon radio-frequency glow Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

show that application of a radio-frequency... during the power on' (active glow) fraction of the cycle. A transition from an electron-dominated plasma... D models. The...

74

Understanding Pound-Drever-Hall locking using voltage controlled radio-frequency oscillators: An undergraduate experiment  

E-Print Network [OSTI]

A senior undergraduate experiment has been developed for learning about frequency stabilization techniques using radio-frequency electronics. The primary objective is to frequency stabilize a voltage controlled oscillator to a cavity resonance at 800 MHz using the Pound-Drever-Hall scheme. This technique is commonly applied to stabilize lasers at optical frequencies, but by using radio-frequency equipment exclusively it is possible to systematically study various aspects of the technique more thoroughly, inexpensively, and free from eye hazards. Students also learn about modular radio-frequency electronics and basic feedback control loops. By varying the temperature of the resonator, the students may determine the thermal expansion coefficients of copper, aluminum, and super invar.

Liekhus-Schmaltz, C E

2011-01-01T23:59:59.000Z

75

Investigation of inherent radio frequency oscillation and minor switching in amorphous chalcogenide semiconductors  

E-Print Network [OSTI]

INVESTIGATION OF INHERENT RADIO FREQUENCY OSCILLATION AND MINOR SWITCHING IN AMORPHOUS CHALCOGENIDE SEMICONDUCTORS A Thesis by ROBERT WAYNE GILL JR. Submitted to the Graduate College of Texas AAM University in partial fulfillment... of the requirement for the degree of MASTER OF SCIENCE August 1971 Major Subject: Electrical Engineering INVESTIGATION OF INHERENT RADIO FREQUENCY OSCILLATION AND MINOR SWITCHING IN AMORPHOUS CHALCOGENIDE SEMICONDUCTORS A Thesis by ROBERT WAYNE GILL JR...

Gill, Robert Wayne

1971-01-01T23:59:59.000Z

76

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

SciTech Connect (OSTI)

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.

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

2014-01-06T23:59:59.000Z

77

Radio Frequency Station - Beam Dynamics Interaction in Circular Accelerators  

SciTech Connect (OSTI)

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

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

2011-03-01T23:59:59.000Z

78

Energy Saving Glass Lamination via Selective Radio Frequency Heating  

SciTech Connect (OSTI)

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

Allan, Shawn M.

2012-02-27T23:59:59.000Z

79

Energy Saving Glass Lamination via Selective Radio Frequency Heating  

SciTech Connect (OSTI)

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

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

2012-02-27T23:59:59.000Z

80

Understanding Pound-Drever-Hall locking using voltage controlled radio-frequency oscillators: An undergraduate experiment  

E-Print Network [OSTI]

Understanding Pound-Drever-Hall locking using voltage controlled radio-frequency oscillators. The three main pieces of equipment are a commercial voltage controlled oscillator, a resonating cavity of the voltage controlled oscillator. The cavity resonance is then observed by scanning the frequency

Le Roy, Robert J.

Note: This page contains sample records for the topic "radio frequency identification" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Radio Frequency Identification (RFID) Stakeholder Meeting Dallas, Texas  

E-Print Network [OSTI]

Discussion Points · Participants highlighted the need to establish performance criteria and business rules Associations, with assistance of EPA Region 6 and Texas Commission on Environmental Quality. · Texas of Enforcement and Compliance Assurance Davis Jones, U.S. EPA Office of Enforcement and Compliance Assurance

82

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

SciTech Connect (OSTI)

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.

Bora, B.; Bhuyan, H.; Favre, M.; Wyndham, E.; Chuaqui, H. [Facultad de Fisica, Pontificia Universidad Catolica de Chile, Ave. Vicuna Mackenna 4860, Santiago 22 (Chile); Kakati, M. [Thermal Plasma Processed Materials Laboratory, Centre of Plasma Physics, Institute for Plasma Research, Sonapur 782 402, Assam (India)

2011-10-15T23:59:59.000Z

83

Resistance Compression Networks for Radio-Frequency Power Conversion  

E-Print Network [OSTI]

A limitation of many high-frequency resonant inverter topologies is their high sensitivity to loading conditions. This paper introduces a new class of matching networks that greatly reduces the load sensitivity of resonant ...

Han, Yehui

84

Single shot time stamping of ultrabright radio frequency compressed electron pulses  

SciTech Connect (OSTI)

We demonstrate a method of time-stamping Radio Frequency compressed electron bunches for Ultrafast Electron Diffraction experiments in the sub-pC regime. We use an in-situ ultra-stable photo-triggered streak camera to directly track the time of arrival of each electron pulse and correct for the timing jitter in the radio frequency synchronization. We show that we can correct for timing jitter down to 30 fs root-mean-square with minimal distortion to the diffraction patterns, and performed a proof-of-principle experiment by measuring the ultrafast electron-phonon coupling dynamics of silicon.

Gao, M.; Dwayne Miller, R. J. [Department of Chemistry and Physics, University of Toronto, Toronto, ON. M5S 3H6 (Canada); Max Planck Research Department for Structural Dynamics, Department of Physics, Center for Free Electron Laser Science, University of Hamburg, DESY, D-22607 Hamburg (Germany); Jiang, Y.; Kassier, G. H. [Max Planck Research Department for Structural Dynamics, Department of Physics, Center for Free Electron Laser Science, University of Hamburg, DESY, D-22607 Hamburg (Germany)

2013-07-15T23:59:59.000Z

85

LowFrequency Solar Radio Bursts from Green Bank  

E-Print Network [OSTI]

waves at the plasma frequency that are converted into fundamental and har- monic electromagnetic waves of emission during the decline of the soft X­rays. The Type III bursts are attributed to beams of keV­energy (UT) 20040716 GBSRBS GOES FIGURE 4: Short­wave fadeout followed by a Type II burst. In this figure

White, Stephen

86

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

SciTech Connect (OSTI)

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.

Donko, Z. [Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Schulze, J.; Czarnetzki, U.; Luggenhoelscher, D. [Institute for Plasma and Atomic Physics, Ruhr-University Bochum, Bochum 44780 (Germany)

2009-03-30T23:59:59.000Z

87

Superconducting Radio Frequency Cavities as Axion Dark Matter Detectors  

E-Print Network [OSTI]

A modification of the cavity technique for axion dark matter detection is described in which the cavity is driven with input power instead of being permeated by a static magnetic field. A small fraction of the input power is pumped by the axion field to a receiving mode of frequency $\\omega_1$ when the resonance condition $\\omega_1 = \\omega_0 \\pm m_a$ is satisfied, where $\\omega_0$ is the frequency of the input mode and $m_a$ the axion mass. The relevant form factor is calculated for any pair of input and output modes in a cylindrical cavity. The overall search strategy is discussed and the technical challenges to be overcome by an actual experiment are listed.

P. Sikivie

2013-01-20T23:59:59.000Z

88

The low-frequency environment of the Murchison Widefield Array: radio-frequency interference analysis and mitigation  

E-Print Network [OSTI]

The Murchison Widefield Array (MWA) is a new low-frequency interferometric radio telescope built in Western Australia at one of the locations of the future Square Kilometre Array (SKA). We describe the automated radio-frequency interference (RFI) detection strategy implemented for the MWA, which is based on the AOFlagger platform, and present 72-231-MHz RFI statistics from 10 observing nights. RFI detection removes 1.1% of the data. RFI from digital TV (DTV) is observed 3% of the time due to occasional ionospheric or atmospheric propagation. After RFI detection and excision, almost all data can be calibrated and imaged without further RFI mitigation efforts, including observations within the FM and DTV bands. The results are compared to a previously published Low-Frequency Array (LOFAR) RFI survey. The remote location of the MWA results in a substantially cleaner RFI environment compared to LOFAR's radio environment, but adequate detection of RFI is still required before data can be analysed. We include speci...

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

2015-01-01T23:59:59.000Z

89

Holme et al. Soil Redox Sensor Networks RADIO FREQUENCY ENABLED SOIL REDOX POTENTIAL  

E-Print Network [OSTI]

Holme et al. Soil Redox Sensor Networks RADIO FREQUENCY ENABLED SOIL REDOX POTENTIAL SENSOR technologies that may be combined into a cost effective soil redox sensor network, discuss the merits of each as a component of said network, describe a prototype soil redox sensor network and perform basic laboratory

Rubinstein, Benjamin

90

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

E-Print Network [OSTI]

Controller design issues in the feedback control of radio frequency plasma processing reactors feedback control of inductively coupled plasma processing reactors for polysilicon etching and be successfully used for feedback control of plasma processing reactors.4 There are many control strate- gies

Kushner, Mark

91

High-rate chemical vapor deposition of nanocrystalline silicon carbide films by radio frequency thermal plasma  

E-Print Network [OSTI]

High-rate chemical vapor deposition of nanocrystalline silicon carbide films by radio frequency Semiconductor, Eden Prairie, MN, USA Received 10 July 2002; accepted 14 July 2002 Abstract Silicon carbide films; Nanomaterials; Silicon carbide; Thermal plasmas; Thin films; Si tetrachlorine precursor Silicon carbide has

Zachariah, Michael R.

92

Stochastic electron heating in bounded radio-frequency plasmas I. D. Kaganovich,a)  

E-Print Network [OSTI]

Stochastic electron heating in bounded radio-frequency plasmas I. D. Kaganovich,a) V. I. Kolobov Received 2 November 1995; accepted for publication 7 October 1996 The mechanisms of electron heating in low for the stochastic heating. A classification of heating regimes is performed and expressions for the power deposition

Kaganovich, Igor

93

Two-Dimensional Numerical Modeling of Radio-Frequency Ion Engine Discharge  

E-Print Network [OSTI]

, Manuel Martinez-Sanchez August 2010 SSL # 14-10 #12;2 #12;3 Two-Dimensional Numerical Modeling of Radio-Frequency Ion Engine Discharge Michael Meng-Tsuan Tsay, Manuel Martinez-Sanchez August 2010 SSL # 14

94

Sensitivity of the Kurtosis Statistic as a Detector of Pulsed Sinusoidal Radio Frequency Interference in a  

E-Print Network [OSTI]

Sensitivity of the Kurtosis Statistic as a Detector of Pulsed Sinusoidal Radio Frequency to identify. The kurtosis statistic is a tool being explored as a means of detecting low level RFI in microwave receivers. The performance of the kurtosis statistic as a detector of RFI is introduced. Keywords

Ruf, Christopher

95

Using Multiple Beams to Distinguish Radio Frequency Interference from SETI Signals  

E-Print Network [OSTI]

Using Multiple Beams to Distinguish Radio Frequency Interference from SETI Signals G. R. Harp Allen for extra-terrestrial intelligence) observations. It is a multi-beam instrument, with 16 independently steerable dual- polarization beams at 4 different tunings. Given 4 beams at one tuning, it is possible

Ellingson, Steven W.

96

Impact of Mobile Transmitter Sources on Radio Frequency Wireless Energy Harvesting  

E-Print Network [OSTI]

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

Sanyal, Sugata

97

Radio-nuclide mixture identification using medium energy resolution detectors  

DOE Patents [OSTI]

According to one embodiment, a method for identifying radio-nuclides includes receiving spectral data, extracting a feature set from the spectral data comparable to a plurality of templates in a template library, and using a branch and bound method to determine a probable template match based on the feature set and templates in the template library. In another embodiment, a device for identifying unknown radio-nuclides includes a processor, a multi-channel analyzer, and a memory operatively coupled to the processor, the memory having computer readable code stored thereon. The computer readable code is configured, when executed by the processor, to receive spectral data, to extract a feature set from the spectral data comparable to a plurality of templates in a template library, and to use a branch and bound method to determine a probable template match based on the feature set and templates in the template library.

Nelson, Karl Einar

2013-09-17T23:59:59.000Z

98

Coupling effects in inductive discharges with radio frequency substrate biasing  

SciTech Connect (OSTI)

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

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

2012-01-09T23:59:59.000Z

99

ULTRA STEEP SPECTRUM RADIO SOURCES IN THE LOCKMAN HOLE: SERVS IDENTIFICATIONS AND REDSHIFT DISTRIBUTION AT THE FAINTEST RADIO FLUXES  

SciTech Connect (OSTI)

Ultra steep spectrum (USS) radio sources have been successfully used to select powerful radio sources at high redshifts (z {approx}> 2). Typically restricted to large-sky surveys and relatively bright radio flux densities, it has gradually become possible to extend the USS search to sub-mJy levels, thanks to the recent appearance of sensitive low-frequency radio facilities. Here a first detailed analysis of the nature of the faintest USS sources is presented. By using Giant Metrewave Radio Telescope and Very Large Array radio observations of the Lockman Hole at 610 MHz and 1.4 GHz, a sample of 58 USS sources, with 610 MHz integrated fluxes above 100 {mu}Jy, is assembled. Deep infrared data at 3.6 and 4.5 {mu}m from the Spitzer Extragalactic Representative Volume Survey (SERVS) are used to reliably identify counterparts for 48 (83%) of these sources, showing an average total magnitude of [3.6]{sub AB} = 19.8 mag. Spectroscopic redshifts for 14 USS sources, together with photometric redshift estimates, improved by the use of the deep SERVS data, for a further 19 objects, show redshifts ranging from z = 0.1 to z = 2.8, peaking at z {approx} 0.6 and tailing off at high redshifts. The remaining 25 USS sources, with no redshift estimate, include the faintest [3.6] magnitudes, with 10 sources undetected at 3.6 and 4.5 {mu}m (typically [3.6] {approx}> 22-23 mag from local measurements), which suggests the likely existence of higher redshifts among the sub-mJy USS population. The comparison with the Square Kilometre Array Design Studies Simulated Skies models indicates that Fanaroff-Riley type I radio sources and radio-quiet active galactic nuclei may constitute the bulk of the faintest USS population, and raises the possibility that the high efficiency of the USS technique for the selection of high-redshift sources remains even at the sub-mJy level.

Afonso, J.; Bizzocchi, L.; Grossi, M.; Messias, H.; Fernandes, C. A. C. [Observatorio Astronomico de Lisboa, Faculdade de Ciencias, Universidade de Lisboa, Tapada da Ajuda, 1349-018 Lisbon (Portugal); Ibar, E.; Ivison, R. J. [UK Astronomy Technology Centre, Royal Observatory, Edinburgh EH9 3HJ (United Kingdom); Simpson, C. [Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead CH41 1LD (United Kingdom); Chapman, S.; Gonzalez-Solares, E. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Jarvis, M. J. [Centre for Astrophysics, Science and Technology Research Institute, University of Hertfordshire, Hatfield, Herts AL10 9AB (United Kingdom); Rottgering, H. [Leiden Observatory, Leiden University, Oort Gebouw, P.O. Box 9513, 2300 RA Leiden (Netherlands); Norris, R. P. [CSIRO Astronomy and Space Science, P.O. Box 76, Epping, NSW 1710 (Australia); Dunlop, J.; Best, P. [SUPA, Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Pforr, J. [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth PO1 3FX (United Kingdom); Vaccari, M. [Department of Astronomy, University of Padova, vicolo Osservatorio 3, 35122 Padova (Italy); Seymour, N. [Mullard Space Science Laboratory, UCL, Holmbury St Mary, Dorking, Surrey RH5 6NT (United Kingdom); Farrah, D. [Astronomy Centre, Department of Physics and Astronomy, University of Sussex, Brighton BN1 9QH (United Kingdom); Huang, J.-S., E-mail: jafonso@oal.ul.pt [Department of Astrophysics, Oxford University, Keble Road, Oxford OX1 3RH (United Kingdom); and others

2011-12-20T23:59:59.000Z

100

Response of radio frequency superconducting quantum interference devices to electromagnetic interference  

SciTech Connect (OSTI)

A number of applications of high-temperature superconductor radio frequency superconducting quantum interference devices (rf SQUIDs) require a certain immunity of these sensors against electromagnetic interference (EMI). We have investigated effects of electromagnetic radiation in the high-frequency and ultrahigh-frequency range on various types of rf SQUIDs. It has been found that EMI of sufficient field strength reduces the voltage versus flux transfer function, and thus increases the flux noise of the SQUIDs. SQUIDs with a wire wound tank circuit coil have been found to be more sensitive to EMI than SQUIDs integrated into a superconducting microstrip resonator. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

Mueck, M.; Dechert, J.; Gail, J.; Kreutzbruck, M.; Schoene, S.; Weidl, R. [Institut fuer Angewandte Physik, Justus-Liebig-Universitaet Giessen, Heinrich-Buff-Ring 16, 35392 Giessen (Germany)] [Institut fuer Angewandte Physik, Justus-Liebig-Universitaet Giessen, Heinrich-Buff-Ring 16, 35392 Giessen (Germany)

1995-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "radio frequency identification" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Frequency effects on the production of reactive oxygen species in atmospheric radio frequency helium-oxygen discharges  

SciTech Connect (OSTI)

Several experimental and computational studies have shown that increasing frequency can effectively enhance the discharge stability in atmospheric radio-frequency (rf) discharges, but the frequency effects on the reactivity of rf discharges, represented by the densities of reactive oxygen species (ROS), are still far from fully understood. In this paper, a one-dimensional fluid model with 17 species and 65 reactions taken into account is used to explore the influences of the driving frequency on the production and destruction of ROS in atmospheric rf helium-oxygen discharges. From the computational results, with an increase in the frequency the densities of ROS decrease always at a constant power density, however, in the relatively higher frequency discharges the densities of ROS can be effectively improved by increasing the input power density with an expanded oxygen admixture range, while the discharges operate in the {alpha} mode, and the numerical data also show the optimal oxygen admixture for ground state atomic oxygen, at which the peak atomic oxygen density can be obtained, increases with the driving frequency.

Zhang, Yuantao T.; He Jin [Shandong Provincial Key Lab of UHV Technology and Gas Discharge Physics, School of Electrical Engineering, Shandong University, Jinan, Shandong Province 250061 (China)

2013-01-15T23:59:59.000Z

102

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

SciTech Connect (OSTI)

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.

Oberoi, Divya; Matthews, Lynn D.; Lonsdale, Colin J.; Benkevitch, Leonid [MIT Haystack Observatory, Westford, MA (United States); Cairns, Iver H.; Lobzin, Vasili [School of Physics, University of Sydney, Sydney (Australia); Emrich, David; Wayth, Randall B.; Arcus, Wayne [Curtin Institute for Radio Astronomy, Curtin University, Perth (Australia); Morgan, Edward H.; Williams, Christopher [MIT Kavli Institute for Astrophysics and Space Research, Cambridge, MA (United States); Prabu, T.; Vedantham, Harish [Raman Research Institute, Bangalore (India); Williams, Andrew [Perth Observatory, The University of Western Australia, Perth (Australia); White, Stephen M. [Air Force Research Laboratory, Kirtland, NM (United States); Allen, G. [CSIRO Astronomy and Space Science, Epping, NSW (Australia); Barnes, David [Center for Astrophysics and Supercomputing, Swinburne University of Technology, Melbourne (Australia); Bernardi, Gianni [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Bowman, Judd D. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ (United States); Briggs, Frank H. [Research School of Astronomy and Astrophysics, The Australian National University, Canberra (Australia)

2011-02-20T23:59:59.000Z

103

Scattering of Radio Frequency Waves by Edge Density Blobs in Tokamak Plasmas  

SciTech Connect (OSTI)

The density blobs and fluctuations present in the edge region of magnetic fusion devices can scatter radio frequency (RF) waves through refraction and diffraction. The scattering can diffuse the rays in space and in wave-vector space. The diffusion in space can make the rays miss their intended target region, while the diffusion in wave-vector space can broaden the wave spectrum and modify the wave damping and current profile.

Ram, A. K. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Hizanidis, K.; Kominis, Y. [National Technical University of Athens, Association EURATOM-Hellenic Republic, Zografou, Athens 15773 (Greece)

2011-12-23T23:59:59.000Z

104

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

DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

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

Ciovati, Gianluigi; Baldwin, Charles; Cheng, Guangfeng; Flood, Roger; Jordan, Kevin; Kneisel, Peter; Morrone, Michael; Nemes, George; Turlington, Larry; Wang, Haipeng; Wilson, Katherine

2012-03-16T23:59:59.000Z

105

First Spectroscopic Imaging Observations of the Sun at Low Radio Frequencies with the Murchison Widefield Array Prototype  

E-Print Network [OSTI]

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. ...

Oberoi, Divya

106

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

E-Print Network [OSTI]

for the transmission of one packet. Joint blind channel and CFO estimation over multiple frequency bursts is considered, achieves the joint CRB over multiple bursts. In the second part of the paper, some practical blind at each RFB and changes independently from block to block (block fading model [1]). Knowing

Yýlmaz, �zgür

107

Investigation of effect of excitation frequency on electron energy distribution functions in low pressure radio frequency bounded plasmas  

SciTech Connect (OSTI)

Particle in cell (PIC) simulations are employed to investigate the effect of excitation frequency {omega} on electron energy distribution functions (EEDFs) in a low pressure radio frequency (rf) discharge. The discharge is maintained over a length of 0.10 m, bounded by two infinite parallel plates, with the coherent heating field localized at the center of the discharge over a distance of 0.05 m and applied perpendicularly along the y and z directions. On varying the excitation frequency f (={omega}/2{pi}) in the range 0.01-50 MHz, it is observed that for f {<=} 5 MHz the EEDF shows a trend toward a convex (Druyvesteyn-like) distribution. For f > 5 MHz, the distribution resembles more like a Maxwellian with the familiar break energy visible in most of the distributions. A prominent ''hot tail'' is observed at f{>=} 20 MHz and the temperature of the tail is seen to decrease with further increase in frequency (e.g., at 30 MHz and 50 MHz). The mechanism for the generation of the ''hot tail'' is considered to be due to preferential transit time heating of energetic electrons as a function of {omega}, in the antenna heating field. There exists an optimum frequency for which high energy electrons are maximally heated. The occurrence of the Druyvesteyn-like distributions at lower {omega} may be explained by a balance between the heating of the electrons in the effective electric field and elastic cooling due to electron neutral collision frequency {nu}{sub en}; the transition being dictated by {omega} {approx} 2{pi}{nu}{sub en}.

Bhattacharjee, Sudeep [Space plasma, Power and Propulsion, Research School of Physics and Engineering, Australian National University, Canberra ACT 0200 (Australia); Department of Physics, Indian Institute of Technology, Kanpur 208 016 (India); Lafleur, Trevor; Charles, Christine; Boswell, Rod [Space plasma, Power and Propulsion, Research School of Physics and Engineering, Australian National University, Canberra ACT 0200 (Australia)

2011-07-15T23:59:59.000Z

108

MULTI-FREQUENCY STUDIES OF RADIO RELICS IN THE GALAXY CLUSTERS A4038, A1664, AND A786  

SciTech Connect (OSTI)

We present a multi-frequency study of radio relics associated with the galaxy clusters A4038, A1664, and A786. Radio images, integrated spectra, spectral index maps, and fits to the integrated spectra in the framework of the adiabatic compression model are presented. Images of the relic in A4038 at 150, 240, and 606 MHz with the Giant Meterwave Radio Telescope have revealed extended ultra-steep spectrum ({alpha} {approx} -1.8 to -2.7) emission of extent 210 Multiplication-Sign 80 kpc{sup 2}. The model of passively evolving radio lobes compressed by a shock fits the integrated spectrum best. The relic with a circular morphology at the outskirts of the cluster A1664 has an integrated spectral index of {approx} - 1.10 {+-} 0.06 and is best fit by the model of radio lobes lurking for {approx}4 Multiplication-Sign 10{sup 7} yr. The relic near A786 has a curved spectrum and is best fit by a model of radio lobes lurking for {approx}3 Multiplication-Sign 10{sup 7} yr. At 4.7 GHz, a compact radio source, possibly the progenitor of the A786 relic, is detected near the center of the radio relic. The A786 radio relic is thus likely a lurking radio galaxy rather than a site of cosmological shock as has been considered in earlier studies.

Kale, Ruta; Dwarakanath, K. S., E-mail: ruta@iucaa.ernet.in [Raman Research Institute, C. V. Raman Avenue, Sadashivanagar, Bangalore 560 080 (India)

2012-01-01T23:59:59.000Z

109

Electron properties and air mixing in radio frequency driven argon plasma jets at atmospheric pressure  

SciTech Connect (OSTI)

A time modulated radio frequency (RF) plasma jet operated with an Ar mixture is investigated by measuring the electron density and electron temperature using Thomson scattering. The measurements have been performed spatially resolved for two different electrode configurations and as a function of the plasma dissipated power and air concentration admixed to the Ar. Time resolved measurements of electron densities and temperatures during the RF cycle and after plasma power switch-off are presented. Furthermore, the influence of the plasma on the air entrainment into the effluent is studied using Raman scattering.

Gessel, Bram van; Bruggeman, Peter [Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands)] [Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands); Brandenburg, Ronny [Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands) [Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands); Leibniz Institute for Plasma Science and Technology (INP Greifswald), Felix-Hausdorff-Str. 2, D-17489 Greifswald (Germany)

2013-08-05T23:59:59.000Z

110

A prototype system for detecting the radio-frequency pulse associated with cosmic ray air showers  

E-Print Network [OSTI]

The development of a system to detect the radio-frequency (RF) pulse associated with extensive air showers of cosmic rays is described. This work was performed at the CASA/MIA array in Utah, with the intention of designing equipment that can be used in conjunction with the Auger Giant Array. A small subset of data (less than 40 out of a total of 600 hours of running time), taken under low-noise conditions, permitted upper limits to be placed on the rate for pulses accompanying showers of energies around $10^{17}$ eV.

Green, K; Suprun, D A; Wilkerson, J F; Green, Kevin; Rosner, Jonathan L.; Suprun, Denis A.

2003-01-01T23:59:59.000Z

111

A prototype system for detecting the radio-frequency pulse associated with cosmic ray air showers  

E-Print Network [OSTI]

The development of a system to detect the radio-frequency (RF) pulse associated with extensive air showers of cosmic rays is described. This work was performed at the CASA/MIA array in Utah, with the intention of designing equipment that can be used in conjunction with the Auger Giant Array. A small subset of data (less than 40 out of a total of 600 hours of running time), taken under low-noise conditions, permitted upper limits to be placed on the rate for pulses accompanying showers of energies around $10^{17}$ eV.

Kevin Green; Jonathan L. Rosner; Denis A. Suprun; J. F. Wilkerson

2003-04-14T23:59:59.000Z

112

VLBA Multi-frequency Polarimetric imaging of Radio-loud Broad Absorption Line Quasars  

E-Print Network [OSTI]

We conducted the first multi-frequency polarimetric imaging of four broad absorption line (BAL) quasars using Very Long Baseline Array at milli-arcsecond resolutions to investigate the inclination of the non-thermal jet and test the hypothesis that radio sources in BAL quasars are still young. Among these four sources, J0928+446, J1018+0530, and J1405+4056 show one-sided structures in parsec scales, and polarized emission detected in the core. These characteristics are consistent with those of blazars. We set constraints on viewing angles to $wind.

Hayashi, Takayuki J; Nagai, Hiroshi

2013-01-01T23:59:59.000Z

113

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

SciTech Connect (OSTI)

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

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

2011-03-01T23:59:59.000Z

114

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

SciTech Connect (OSTI)

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

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

2014-06-09T23:59:59.000Z

115

Augmenting real data with synthetic data: an application in assessing radio-isotope identification algorithms  

SciTech Connect (OSTI)

The performance of Radio-Isotope Identification (RIID) algorithms using gamma spectroscopy is increasingly important. For example, sensors at locations that screen for illicit nuclear material rely on isotope identification to resolve innocent nuisance alarms arising from naturally occurring radioactive material. Recent data collections for RIID testing consist of repeat measurements for each of several scenarios to test RIID algorithms. Efficient allocation of measurement resources requires an appropriate number of repeats for each scenario. To help allocate measurement resources in such data collections for RIID algorithm testing, we consider using only a few real repeats per scenario. In order to reduce uncertainty in the estimated RIID algorithm performance for each scenario, the potential merit of augmenting these real repeats with realistic synthetic repeats is also considered. Our results suggest that for the scenarios and algorithms considered, approximately 10 real repeats augmented with simulated repeats will result in an estimate having comparable uncertainty to the estimate based on using 60 real repeats.

Burr, Tom L [Los Alamos National Laboratory; Hamada, Michael [Los Alamos National Laboratory; Graves, Todd [Los Alamos National Laboratory; Myers, Steve [Los Alamos National Laboratory

2008-01-01T23:59:59.000Z

116

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

E-Print Network [OSTI]

"; Penticton, Canada, 16-18 July 2004 "Quiet, please!" - regulatory protection strategies for the SKA Wim van of the large financial investment foreseen in the Square Kilometre Array (SKA) radio telescope, it will need sensitive observations outside the frequency bands allocated by the International Telecommunication Union

Ellingson, Steven W.

117

Elimination of Radio-Frequency Noise by Identifying and Diverting Large RF Ground Currents  

SciTech Connect (OSTI)

The problem of electromagnetic interference in scientific instruments is compounded for high-power plasma experiments by the large currents and voltages as well as by the broad bandwidths of the instruments. Ground loops are known to allow stray magnetic fields to drive large ground currents that can induce spurious signals and damage electronics. Furthermore, even when a ground loop is broken, capacitive coupling can still permit the flow of radio-frequency current, resulting in high-frequency spurious signals that can overwhelm the desired signal. We present the effects of RF ground loops on the output of vacuum photodiodes used in the Caltech Solar Loop Experiment and demonstrate the elimination of the spurious signals by diverting the ground currents away from the most vulnerable point of the signal line. Techniques for identifying the RF ground loops are also discussed. These techniques should be valuable in many high-power systems where interference from spurious coupling is an issue.

Perkins, R. J.; Bellan, P. M. [Applied Physics, California Institute of Technology (United States)

2011-12-23T23:59:59.000Z

118

Spin-torque diode radio-frequency detector with voltage tuned resonance  

SciTech Connect (OSTI)

We report on a voltage-tunable radio-frequency (RF) detector based on a magnetic tunnel junction (MTJ). The spin-torque diode effect is used to excite and/or detect RF oscillations in the magnetic free layer of the MTJ. In order to reduce the overall in-plane magnetic anisotropy of the free layer, we take advantage of the perpendicular magnetic anisotropy at the interface between ferromagnetic and insulating layers. The applied bias voltage is shown to have a significant influence on the magnetic anisotropy, and thus on the resonance frequency of the device. This influence also depends on the voltage polarity. The obtained results are accounted for in terms of the interplay of spin-transfer-torque and voltage-controlled magnetic anisotropy effects.

Skowro?ski, Witold, E-mail: skowron@agh.edu.pl; Frankowski, Marek; Stobiecki, Tomasz [AGH University of Science and Technology, Department of Electronics, Al. Mickiewicza 30, 30-059 Kraków (Poland); Wrona, Jerzy [AGH University of Science and Technology, Department of Electronics, Al. Mickiewicza 30, 30-059 Kraków (Poland); Singulus Technologies, Kahl am Main 63796 (Germany); Ogrodnik, Piotr [Faculty of Physics, Warsaw University of Technology, ul. Koszykowa 75, 00-662 Warsaw (Poland); AGH University of Science and Technology, Department of Electronics, Al. Mickiewicza 30, 30-059 Kraków (Poland); Barna?, Józef [Faculty of Physics, Adam Mickiewicz University, ul. Umultowska 85, 61-614 Pozna? (Poland); Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, 60-179 Pozna? (Poland)

2014-08-18T23:59:59.000Z

119

Temperature of hydrogen radio frequency plasma under dechlorination process of polychlorinated biphenyls  

SciTech Connect (OSTI)

It has been reported that RF (radio frequency) hydrogen plasmas promote the dechlorination process of PCBs (polychlorinated biphenyls) under irradiation of MW (microwave). A relative emission intensity spectroscope system was used for single-shot imaging of two-dimensional temperature distributions of RF hydrogen plasmas generated in chemical solutions with several mixing ratios of isopropyl alcohol (IPA) and insulation oil under MW irradiation. Our experimental results showed that the plasma generation frequencies for the oil-contaminating solutions were higher than that for the pure IPA solution. In addition, the plasma temperature in the compound liquids including both oil and IPA was higher than that in the pure IPA and oil solutions. A combination of the plasma temperature measurements and plasma composition analysis indicated that the hydrogen radicals generated in a chemical solution containing the equal volumes of IPA and oil were almost the same amounts of H and H{sup +}, while those produced in the other solutions were mainly H.

Inada, Y., E-mail: inada@hvg.t.u-tokyo.ac.jp; Abe, K.; Kumada, A.; Hidaka, K. [Department of Electrical Engineering and Information Systems, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Amano, K.; Itoh, K.; Oono, T. [R and D Center, Tokyo Electric Power Company, 4-1 Egasaki-cho, Tsurumi-ku, Yokohama 230-8510 (Japan)

2014-10-27T23:59:59.000Z

120

Intelligent Spectrum Sensor Radio.  

E-Print Network [OSTI]

??A cognitive radio is a radio with built-in intelligence that makes it able to utilize the radio frequency spectrum more efficiently by adapting to the… (more)

Mian, Omer

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "radio frequency identification" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Verification of particle simulation of radio frequency waves in fusion plasmas  

SciTech Connect (OSTI)

Radio frequency (RF) waves can provide heating, current and flow drive, as well as instability control for steady state operations of fusion experiments. A particle simulation model has been developed in this work to provide a first-principles tool for studying the RF nonlinear interactions with plasmas. In this model, ions are considered as fully kinetic particles using the Vlasov equation and electrons are treated as guiding centers using the drift kinetic equation. This model has been implemented in a global gyrokinetic toroidal code using real electron-to-ion mass ratio. To verify the model, linear simulations of ion plasma oscillation, ion Bernstein wave, and lower hybrid wave are carried out in cylindrical geometry and found to agree well with analytic predictions.

Kuley, Animesh; Lin, Z. [Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States) [Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States); Fusion Simulation Center, Peking University, Beijing 100871 (China); Wang, Z. X. [Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States)] [Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States); Wessel, F. [Tri Alpha Energy, Inc., Post Office Box 7010, Rancho Santa Margarita, California 92688 (United States)] [Tri Alpha Energy, Inc., Post Office Box 7010, Rancho Santa Margarita, California 92688 (United States)

2013-10-15T23:59:59.000Z

122

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

SciTech Connect (OSTI)

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

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

2012-04-01T23:59:59.000Z

123

Coupled microwave ECR and radio-frequency plasma source for plasma processing  

DOE Patents [OSTI]

In a dual plasma device, the first plasma is a microwave discharge having its own means of plasma initiation and control. The microwave discharge operates at electron cyclotron resonance (ECR), and generates a uniform plasma over a large area of about 1000 cm[sup 2] at low pressures below 0.1 mtorr. The ECR microwave plasma initiates the second plasma, a radio frequency (RF) plasma maintained between parallel plates. The ECR microwave plasma acts as a source of charged particles, supplying copious amounts of a desired charged excited species in uniform manner to the RF plasma. The parallel plate portion of the apparatus includes a magnetic filter with static magnetic field structure that aids the formation of ECR zones in the two plasma regions, and also assists in the RF plasma also operating at electron cyclotron resonance. 4 figures.

Tsai, C.C.; Haselton, H.H.

1994-03-08T23:59:59.000Z

124

Laser polishing of niobium for application to superconducting radio frequency cavities  

SciTech Connect (OSTI)

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.

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

2012-09-01T23:59:59.000Z

125

Simulation of direct plasma injection for laser ion beam acceleration with a radio frequency quadrupole  

SciTech Connect (OSTI)

The direct plasma injection scheme (DPIS) has been being studied at Institute of Modern Physics since several years ago. A C{sup 6+} beam with peak current of 13 mA, energy of 593 keV/u has been successfully achieved after acceleration with DPIS method. To understand the process of DPIS, some simulations have been done as follows. First, with the total current intensity and the relative yields of different charge states for carbon ions measured at the different distance from the target, the absolute current intensities and time-dependences for different charge states are scaled to the exit of the laser ion source in the DPIS. Then with these derived values as the input parameters, the extraction of carbon beam from the laser ion source to the radio frequency quadrupole with DPIS is simulated, which is well agreed with the experiment results.

Jin, Q. Y.; Li, Zh. M.; Liu, W. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); School of Physics, University of Chinese Academy of Sciences, Beijing 100049 (China); Zhao, H. Y., E-mail: zhaohy@impcas.ac.cn; Zhang, J. J.; Sha, Sh.; Zhang, Zh. L.; Zhang, X. Zh.; Sun, L. T.; Zhao, H. W. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

2014-07-15T23:59:59.000Z

126

High power water load for microwave and millimeter-wave radio frequency sources  

DOE Patents [OSTI]

A high power water load for microwave and millimeter wave radio frequency sources has a front wall including an input port for the application of RF power, a cylindrical dissipation cavity lined with a dissipating material having a thickness which varies with depth, and a rear wall including a rotating reflector for the reflection of wave energy inside the cylindrical cavity. The dissipation cavity includes a water jacket for removal of heat generated by the absorptive material coating the dissipation cavity, and this absorptive material has a thickness which is greater near the front wall than near the rear wall. Waves entering the cavity reflect from the rotating reflector, impinging and reflecting multiple times on the absorptive coating of the dissipation cavity, dissipating equal amounts of power on each internal reflection.

Ives, R. Lawrence (Saratoga, CA); Mizuhara, Yosuke M. (Palo Alto, CA); Schumacher, Richard V. (Sunnyvale, CA); Pendleton, Rand P. (Saratoga, CA)

1999-01-01T23:59:59.000Z

127

Feasibility study of a decelerating radio frequency quadrupole system for the antiproton decelerator AD  

E-Print Network [OSTI]

This feasibility study reports on a decelerating Radio-Frequency Quadrupole (RFQ) system for post-deceleration of the 100 MeV/c antiproton beam of the AD machine. The corresponding kinetic energy of 5.314 MeV is reduced to values which can be chosen between 10 to 100 keV with minimal blow-up of the normalised beam emittances. This wide range of output energy is required for the second phase of the ASACUSA experiment; it is achieved by electrostatic means. The study gives details of the overall performance of the system, the proposed implementation of the RFQ, the associated rf equipment, the beam lines, the diagnostics as well as estimations for the cost and the manpower requirements of the project.

Bosser, Jacques; Brouet, M; Couturier, B; Gelato, G; Giovannozzi, Massimo; Grandclaude, F; Hémery, J Y; Lombardi, A M; Mikkelsen, U; Maury, S; Möhl, D; Pedersen, F; Pirkl, Werner; Raich, U; Umstätter, H H; Vretenar, Maurizio

1998-01-01T23:59:59.000Z

128

Supersonic combustion of a transverse injected H sub 2 jet in a radio frequency heated flow  

SciTech Connect (OSTI)

The combustion of a single hydrogen jet, normally injected into a radio frequency (RF) heated, oxidant-containing, supersonic flow, has been established to characterize the chemical and fluid dynamic phenomena associated with the reaction process and ultimately validate the predictive capability of computational computer dynamic (CFD) codes. The experimental system employed for this study is unique in that it uses an electrodeless, inductively coupled plasma tube to generate the high temperature oxidant-containing gas for subsequent nozzle expansion. Advantages of an RF heated flow system include reduced free-stream chemical contamination, continuous operation, and relative ease of integration into a typical flow laboratory environment. A description of the system utilized for this study is presented including preliminary results of the reactive flow characterization. In addition, the use of the laser-based diagnostic techniques, such as planar laser-induced fluorescence (PLIF), for measuring flow properties is also discussed. 8 refs., 7 figs.

Wantuck, P.J.; Tennant, R.A.; Watanabe, H.H.

1991-01-01T23:59:59.000Z

129

Radio-frequency dispersive detection of donor atoms in a field-effect transistor  

SciTech Connect (OSTI)

Radio-frequency dispersive read-out can provide a useful probe to nano-scale structures, such as nano-wire devices, especially, when the implementation of charge sensing is not straightforward. Here, we demonstrate dispersive “gate-only” read-out of phosphor donors in a silicon nano-scale transistor. The technique enables access to states that are only tunnel-coupled to one contact, which is not easily achievable by other methods. This allows us to locate individual randomly placed donors in the device channel. Furthermore, the setup is naturally compatible with high bandwidth access to the probed donor states and may aid the implementation of a qubit based on coupled donors.

Verduijn, J., E-mail: a.verduijn@unsw.edu.au; Rogge, S. [Centre for Quantum Computation and Communication Technology, University of New South Wales, Sydney NSW 2052 (Australia)] [Centre for Quantum Computation and Communication Technology, University of New South Wales, Sydney NSW 2052 (Australia); Vinet, M. [CEA/LETI-MINATEC, CEA-Grenoble, 17 rue des martyrs, F-38054 Grenoble (France)] [CEA/LETI-MINATEC, CEA-Grenoble, 17 rue des martyrs, F-38054 Grenoble (France)

2014-03-10T23:59:59.000Z

130

Collisionless electron heating by radio frequency bias in low gas pressure inductive discharge  

SciTech Connect (OSTI)

We show experimental observations of collisionless electron heating by the combinations of the capacitive radio frequency (RF) bias power and the inductive power in low argon gas pressure RF biased inductively coupled plasma (ICP). With small RF bias powers in the ICP, the electron energy distribution (EED) evolved from bi-Maxwellian distribution to Maxwellian distribution by enhanced plasma bulk heating and the collisionless sheath heating was weak. In the capacitive RF bias dominant regime, however, high energy electrons by the RF bias were heated on the EEDs in the presence of the ICP. The collisionless heating mechanism of the high energy electrons transited from collisionless inductive heating to capacitive coupled collisionless heating by the electron bounce resonance in the RF biased ICP.

Lee, Hyo-Chang; Chung, Chin-Wook [Department of Electrical Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of)

2012-12-10T23:59:59.000Z

131

Surface Science Laboratory for Studying the Surfaces of Superconducting Radio Frequency Cavities  

SciTech Connect (OSTI)

A Surface Science Laboratory (SSL) has been established at JLab to study surfaces relevant to superconducting radio frequency (SRF) cavities. Current operational facilities include a scanning electron microscope equipped with energy dispersive x-ray analysis, a secondary ion mass spectrometry, a metallographic optical microscope, a transmission electron microscope, a high precision and large scan area 3-D profilometer, a scanning field emission microscope, and a fully equipped sample preparation room. A scanning Auger microscope is being commissioned, and will be available for routine usage soon. Results from typical examples of the R&D projects on SRF cavities that were supported in the past through the use of the facilities in the SSL will be briefly reported.

Andy Wu

2003-09-01T23:59:59.000Z

132

Push-pull radio frequency circuit with integral transistion to waveguide output  

DOE Patents [OSTI]

A radio frequency circuit for ICRF heating includes a resonant push-pull circuit, a double ridged rectangular waveguide, and a coupling transition which joins the waveguide to the resonant circuit. The resonant circuit includes two cylindrical conductors mounted side by side and two power vacuum tubes attached to respective ends of a cylindrical conductor. A conductive yoke is located at the other end of the cylindrical conductors to short circuit the two cylindrical conductors. The coupling transition includes two relatively flat rectangular conductors extending perpendicular to the longitudinal axes of a respective cylindrical conductor to which the flat conductor is attached intermediate the ends thereof. Conductive side covers and end covers are also provided for forming pockets in the waveguide into which the flat conductors extend when the waveguide is attached to a shielding enclosure surrounding the resonant circuit.

Bennett, Wilfred P. (21 Catskill Ct., Belle Mead, NJ 08502)

1987-01-01T23:59:59.000Z

133

Nanostructural features affecting superconducting radio frequency niobium cavities revealed using TEM and EELS  

E-Print Network [OSTI]

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 formation in the electropolished cavity after 120C baking. Furthermore, we demonstrate that adding 800C hydrogen degassing followed by light buffered chemical polishing restores the hydride formation to the pre-120C bake level. We also show absence of niobium oxides along the grain boundaries and the modifications of the surface oxide upon 120C bake.

Trenikhina, Y; Kwon, J; Zuo, J -M; Zasadzinski, J F

2015-01-01T23:59:59.000Z

134

Radio Frequency Noise Effects on the CERN Large Hadron Collider Beam Diffusion  

SciTech Connect (OSTI)

Radio frequency (rf) accelerating system noise can have a detrimental impact on the Large Hadron Collider (LHC) performance through longitudinal motion and longitudinal emittance growth. A theoretical formalism has been developed to relate the beam and rf station dynamics with the bunch length growth. Measurements were conducted at LHC to determine the performance limiting rf components and validate the formalism through studies of the beam diffusion dependence on rf noise. As a result, a noise threshold was established for acceptable performance which provides the foundation for beam diffusion estimates for higher energies and intensities. Measurements were also conducted to determine the low level rf noise spectrum and its major contributions, as well as to validate models and simulations of this system.

Mastoridis, T.; Baudrenghien, P.; Butterworth, A.; Molendijk, J.; /CERN; Rivetta, C.; Fox, J.D.; /SLAC

2012-04-30T23:59:59.000Z

135

Low-Level Radio Frequency System Development for the National Synchrotron Light Source II  

SciTech Connect (OSTI)

The National Synchrotron Light Source-II (NSLS-II) is a new ultra-bright 3GeV 3rd generation synchrotron radiation light source. The performance goals require operation with a beam current of 500mA and a bunch current of at least 0.5mA. The position and timing specifications of the ultra-bright photon beam imposes a set of stringent requirements on the performance of radio frequency (RF) control. In addition, commissioning and staged installation of damping wigglers and insertion devices requires the flexibility of handling varying beam conditions. To meet these requirements, a digital implementation of the LLRF is chosen, and digital serial links are planned for the system integration. The first prototype of the controller front-end hardware has been built, and is currently being tested.

Ma,H.; Rose, J.

2009-05-04T23:59:59.000Z

136

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

SciTech Connect (OSTI)

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.

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

2012-06-01T23:59:59.000Z

137

Coupled microwave ECR and radio-frequency plasma source for plasma processing  

DOE Patents [OSTI]

In a dual plasma device, the first plasma is a microwave discharge having its own means of plasma initiation and control. The microwave discharge operates at electron cyclotron resonance (ECR), and generates a uniform plasma over a large area of about 1000 cm.sup.2 at low pressures below 0.1 mtorr. The ECR microwave plasma initiates the second plasma, a radio frequency (RF) plasma maintained between parallel plates. The ECR microwave plasma acts as a source of charged particles, supplying copious amounts of a desired charged excited species in uniform manner to the RF plasma. The parallel plate portion of the apparatus includes a magnetic filter with static magnetic field structure that aids the formation of ECR zones in the two plasma regions, and also assists in the RF plasma also operating at electron cyclotron resonance.

Tsai, Chin-Chi (Oak Ridge, TN); Haselton, Halsey H. (Knoxville, TN)

1994-01-01T23:59:59.000Z

138

Self-consistent modeling of radio-frequency plasma generation in stellarators  

SciTech Connect (OSTI)

A self-consistent model of radio-frequency (RF) plasma generation in stellarators in the ion cyclotron frequency range is described. The model includes equations for the particle and energy balance and boundary conditions for Maxwell’s equations. The equation of charged particle balance takes into account the influx of particles due to ionization and their loss via diffusion and convection. The equation of electron energy balance takes into account the RF heating power source, as well as energy losses due to the excitation and electron-impact ionization of gas atoms, energy exchange via Coulomb collisions, and plasma heat conduction. The deposited RF power is calculated by solving the boundary problem for Maxwell’s equations. When describing the dissipation of the energy of the RF field, collisional absorption and Landau damping are taken into account. At each time step, Maxwell’s equations are solved for the current profiles of the plasma density and plasma temperature. The calculations are performed for a cylindrical plasma. The plasma is assumed to be axisymmetric and homogeneous along the plasma column. The system of balance equations is solved using the Crank-Nicholson scheme. Maxwell’s equations are solved in a one-dimensional approximation by using the Fourier transformation along the azimuthal and longitudinal coordinates. Results of simulations of RF plasma generation in the Uragan-2M stellarator by using a frame antenna operating at frequencies lower than the ion cyclotron frequency are presented. The calculations show that the slow wave generated by the antenna is efficiently absorbed at the periphery of the plasma column, due to which only a small fraction of the input power reaches the confinement region. As a result, the temperature on the axis of the plasma column remains low, whereas at the periphery it is substantially higher. This leads to strong absorption of the RF field at the periphery via the Landau mechanism.

Moiseenko, V. E., E-mail: moiseenk@ipp.kharkov.ua; Stadnik, Yu. S., E-mail: stadnikys@kipt.kharkov.ua [National Academy of Sciences of Ukraine, National Science Center Kharkov Institute of Physics and Technology (Ukraine); Lysoivan, A. I., E-mail: a.lyssoivan@fz-juelich.de [Royal Military Academy, EURATOM-Belgian State Association, Laboratory for Plasma Physics (Belgium); Korovin, V. B. [National Academy of Sciences of Ukraine, National Science Center Kharkov Institute of Physics and Technology (Ukraine)] [National Academy of Sciences of Ukraine, National Science Center Kharkov Institute of Physics and Technology (Ukraine)

2013-11-15T23:59:59.000Z

139

Noninvasive identification of fluids by swept-frequency acoustic interferometry  

DOE Patents [OSTI]

A method for rapid, noninvasive identification and monitoring of chemicals in sealed containers or containers where direct access to the chemical is not possible is described. Multiple ultrasonic acoustic properties (up to four) of a fluid are simultaneously determined. The present invention can be used for chemical identification and for determining changes in known chemicals from a variety of sources. It is not possible to identify all known chemicals based on the measured parameters, but known classes of chemicals in suspected containers, such as in chemical munitions, can be characterized. In addition, a large number of industrial chemicals can be identified.

Sinha, Dipen N. (Los Alamos, NM)

1998-01-01T23:59:59.000Z

140

Design of multi-channel radio-frequency front-end for 200mhz parallel magnetic resonance imaging  

E-Print Network [OSTI]

increases to 64 or even 128, the traditional method of stacking the same number of radio-frequency (RF) receivers with very low level of integration becomes expensive and cumbersome. However, the cost, size, power consumption of the Parallel MRI receivers...

Liu, Xiaoqun

2009-05-15T23:59:59.000Z

Note: This page contains sample records for the topic "radio frequency identification" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

3742 IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, VOL. 47, NO. 11, NOVEMBER 2009 Microwave Radiometer Radio-Frequency  

E-Print Network [OSTI]

Radiometer Radio-Frequency Interference Detection Algorithms: A Comparative Study Sidharth Misra, Priscilla N is with Halliburton Energy Services, Houston, TX 77032 USA. J. R. Piepmeier is with the Microwave Instrument growth recently in satellite telecommunica- tion, in high-bandwidth point-to-point terrestrial wireless

Ruf, Christopher

142

2012 REU Project Abstracts Identifying Fluids for Tuning and Cooling Radio Frequency Devices Operating in the X-Band  

E-Print Network [OSTI]

2012 REU Project Abstracts Identifying Fluids for Tuning and Cooling Radio Frequency Devices Sapatnekar FPGAs have been used widely for many applications from defense systems to medical equip- ment. Several nanofluidic devices containing arrays of nanochannels with widths between 50 and 500 nm were

Minnesota, University of

143

System efficiency analysis for high power solid state radio frequency transmitter  

SciTech Connect (OSTI)

This paper examines some important relationships, related with the system efficiency, for very high power, radio frequency solid-state transmitter; incorporating multiple solid-state power amplifier modules, power combiners, dividers, couplers, and control/interlock hardware. In particular, the characterization of such transmitters, at the component as well as the system level, is discussed. The analysis for studying the influence of the amplitude and phase imbalance, on useful performance parameters like system efficiency and power distribution is performed. This analysis is based on a scattering parameter model. This model serves as a template for fine-tuning the results, with the help of a system level simulator. For experimental study, this approach is applied to a recently designed modular and scalable solid-state transmitter, operating at the centre frequency of 505.8?MHz and capable of delivering a continuous power of 75 kW. Such first time presented, system level study and experimental characterization for the real time operation will be useful for the high power solid-state amplifier designs, deployed in particle accelerators.

Jain, Akhilesh, E-mail: ajain@rrcat.gov.in; Sharma, D. K.; Gupta, A. K.; Lad, M. R.; Hannurkar, P. R. [RF Systems Division, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India)] [RF Systems Division, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India); Pathak, S. K. [Electromagnetics and Microwave Engineering, Institute for Plasma Research, Gandhinagar 382 428 (India)] [Electromagnetics and Microwave Engineering, Institute for Plasma Research, Gandhinagar 382 428 (India)

2014-02-15T23:59:59.000Z

144

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

SciTech Connect (OSTI)

Micro dielectric barrier discharges (mDBDs) consist of micro-plasma devices (10-100 {mu}m 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{sub 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.

Wang, Jun-Chieh; Kushner, Mark J. [Electrical Engineering and Computer Science Department, University of Michigan, 1301 Beal Ave., Ann Arbor, Michigan 48109 (United States); Leoni, Napoleon; Birecki, Henryk; Gila, Omer [Hewlett Packard Research Labs, Palo Alto, California 94304 (United States)

2013-01-21T23:59:59.000Z

145

Small Satellite Applications of Commercial off the Shelf Radio Frequency Integrated Circuits  

E-Print Network [OSTI]

small satellite, Orbiting Satellite Carrying Amateur Radio (OSCAR) UO-14, was launched in 1990 [15]. While these amateur radio speeds may be sufficient for requirements of the aforementioned missions, they do very little towards expanding future...

Graves, John

2012-02-14T23:59:59.000Z

146

Development of Ultra High Gradient and High Q{sub 0} Superconducting Radio Frequency Cavities  

SciTech Connect (OSTI)

We report on the recent progress at Jefferson Lab in developing ultra high gradient and high Q{sub 0} superconducting radio frequency (SRF) cavities for future SRF based machines. A new 1300 MHz 9-cell prototype cavity is being fabricated. This cavity has an optimized shape in terms of the ratio of the peak surface field (both magnetic and electric) to the acceleration gradient, hence the name low surface field (LSF) shape. The goal of the effort is to demonstrate an acceleration gradient of 50 MV/m with Q{sub 0} of 10{sup 10} at 2 K in a 9-cell SRF cavity. Fine-grain niobium material is used. Conventional forming, machining and electron beam welding method are used for cavity fabrication. New techniques are adopted to ensure repeatable, accurate and inexpensive fabrication of components and the full assembly. The completed cavity is to be first mechanically polished to a mirror-finish, a newly acquired in-house capability at JLab, followed by the proven ILC-style processing recipe established already at JLab. In parallel, new single-cell cavities made from large-grain niobium material are made to further advance the cavity treatment and processing procedures, aiming for the demonstration of an acceleration gradient of 50 MV/m with Q{sub 0} of 2?10{sup 10} at 2K.

Geng, Rongli [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Clemens, William A. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Follkie, James E. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Harris, Teena M. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Kushnick, Peter W. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Machie, Danny [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Martin, Robert E. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Palczewski, Ari D. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Perry, Era A. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Slack, Gary L. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Williams, R. S. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Adolphsen, C. [SLAC, Menlo Park, California, (United States); Li, Z. [SLAC, Menlo Park, California, (United States); Hao, J. K. [Peking University, Beijing (China); Li, Y. M. [Peking University, Beijing (China); Liu, K. X. [Peking University, Beijing (China)

2013-06-01T23:59:59.000Z

147

Matching an H{sup –} beam into a radio frequency quadrupole at Rutherford Appleton Laboratory  

SciTech Connect (OSTI)

A major component of work being carried out to upgrade the ISIS spallation neutron source at Rutherford Appleton Laboratory (RAL) is the Front End Test Stand (FETS). FETS is aimed at improving the luminosity of the linac, and consists of a Penning ion source, Low Energy Beam Transport (LEBT), Radio Frequency Quadrupole (RFQ), and Medium Energy Beam Transport (MEBT). It may serve as a first part of the accelerator chain providing a 60 mA, 3 MeV H{sup –} beam up to a 10% duty cycle. The current output of the source and the transmission of the LEBT are reasonable, but there are issues with the alignment to provide a centred beam matched into the acceptance of the RFQ. Improvements have been made to the post acceleration to address this problem. Measurements with a collimated beam have been performed to understand the behaviour of the solenoids and steerer magnets. Comparing these results with simulations proved that, besides possible mechanical imperfections of the ion source and post acceleration assembly, agreement can only be achieved if the magnetic fields are distorted.

Gabor, C., E-mail: christoph.gabor@stfc.ac.uk; Faircloth, D. C.; Lawrie, S. R.; Letchford, A. P. [STFC, Rutherford Appleton Laboratory, Harwell, Didcot OX11 0QX (United Kingdom)] [STFC, Rutherford Appleton Laboratory, Harwell, Didcot OX11 0QX (United Kingdom); Back, J. J. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom)] [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom)

2014-02-15T23:59:59.000Z

148

Results from sudden loss of vacuum on scaled superconducting radio frequency cryomodule experiment  

SciTech Connect (OSTI)

Superconducting radio frequency (SRF) cavities for particle accelerators are at risk of failure due to sudden loss of vacuum (SLV) adjacent to liquid helium (LHe) spaces. To better understand this failure mode and its associated risks an experiment is designed to test the longitudinal effects of SLV within the beam tube of a scaled SRF cryomodule that has considerable length relative to beam tube cross section. The scaled cryomodule consists of six individual SRF cavities each roughly 350 mm long, initially cooled to 2 K by a superfluid helium bath and a beam tube pumped to vacuum. A fast-acting solenoid valve is used to simulate SLV on the beam tube, from which point it takes over 3 s for the beam tube pressure to equalize with atmosphere, and 30 s for the helium space to reach the relief pressure of 4 bara. A SLV longitudinal effect in the beam tube is evident in both pressure and temperature data, but interestingly the temperatures responds more quickly to SLV than do the pressures. It takes 500 ms (roughly 100 ms per cavity) for the far end of the 2 m long beam tube to respond to a pressure increase compared to 300 ms for temperature (approximately 50 ms per cavity). The paper expands upon these and other results to better understand the longitudinal effect for SRF cryomodules due to SLV.

Dalesandro, Andrew A.; Theilacker, Jay C. [Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States); Dhuley, Ram C.; Van Sciver, Steven W. [National High Magnetic Field Laboratory, Tallahassee, FL 32310 (United States)

2014-01-29T23:59:59.000Z

149

Method of making radio frequency ion source antenna and such antenna  

DOE Patents [OSTI]

In the method, the radio frequency (rf) antenna is made by providing a clean coil made of copper tubing or other metal conductor, which is coated with a tacky organic binder, and then with a powdered glass frit, as by sprinkling the frit uniformly over the binder. The coil is then heated internally in an inert gas atmosphere, preferably by passing an electrical heating current along the coil. Initially, the coil is internally heated to about 200/sup 0/C to boil off the water from the binder, and then to about 750 to 850/sup 0/C to melt the glass frit, while also burning off the organic binder. The melted frit forms a molten glass coating on the metal coil, which is then cooled to solidify the glass, so that the metal coil is covered with a thin continuous homogeneous impervious glass coating of substantially uniform thickness. The glass coating affords complete electrical insulation and complete dielectric protection for the metal coil of the rf antenna, to withstand voltage breakdown and to prevent sputtering, while also doubling the plasma generating efficiency of the rf antenna, when energized with RF power in the vacuum chamber of an ion source for a particle accelerator or the like. The glass frit preferably contains approximately 45% lead oxide.

Ehlers, K.W.; Leung, K.N.

1985-05-22T23:59:59.000Z

150

Loading and Regeneration Analysis of a Diesel Particulate Filter with a Radio Frequency-Based Sensor  

SciTech Connect (OSTI)

Accurate knowledge of diesel particulate filter (DPF) loading is critical for robust and efficient operation of the combined engine-exhaust aftertreatment system. Furthermore, upcoming on-board diagnostics regulations require on-board technologies to evaluate the status of the DPF. This work describes the application of radio frequency (RF) based sensing techniques to accurately measure DPF soot levels and the spatial distribution of the accumulated material. A 1.9L GM turbo diesel engine and a DPF with an RF-sensor were studied. Direct comparisons between the RF measurement and conventional pressure-based methods were made. Further analysis of the particulate matter loading rates was obtained with a mass-based soot emission measurement instrument (TEOM). Comparison with pressure drop measurements show the RF technique is unaffected by exhaust flow variations and exhibits a high degree of sensitivity to DPF soot loading and good dynamic response. Additional computational and experimental work further illustrates the spatial resolution of the RF measurements. Based on the experimental results, the RF technique shows significant promise for improving DPF control enabling optimization of the combined engine-aftertreatment system for improved fuel economy and extended DPF service life.

Sappok, Alex [Filter Sensing Technologies] [Filter Sensing Technologies; Prikhodko, Vitaly Y [ORNL] [ORNL; Parks, II, James E [ORNL

2010-01-01T23:59:59.000Z

151

Charging and discharging in ion implanted dielectric films used for capacitive radio frequency microelectromechanical systems switch  

SciTech Connect (OSTI)

In this work, metal-insulator-semiconductor (MIS) capacitor structure was used to investigate the dielectric charging and discharging in the capacitive radio frequency microelectromechanical switches. The insulator in MIS structure is silicon nitride films (SiN), which were deposited by either low pressure chemical vapor deposition (LPCVD) or plasma enhanced chemical vapor deposition (PECVD) processes. Phosphorus or boron ions were implanted into dielectric layer in order to introduce impurity energy levels into the band gap of SiN. The relaxation processes of the injected charges in SiN were changed due to the ion implantation, which led to the change in relaxation time of the trapped charges. In our experiments, the space charges were introduced by stressing the sample electrically with dc biasing. The effects of implantation process on charge accumulation and dissipation in the dielectric are studied by capacitance-voltage (C-V) measurement qualitatively and quantitatively. The experimental results show that the charging and discharging behavior of the ion implanted silicon nitride films deposited by LPCVD is quite different from the one deposited by PECVD. The charge accumulation in the dielectric film can be reduced by ion implantation with proper dielectric deposition method.

Li Gang; Chen Xuyuan [Pen-Tung Sah Micro-Electro-Mechanical Systems Research Center, Xiamen University, Xiamen, Fujian 361005 (China); Faculty of Science and Engineering, Vestfold University College, P.O. Box 2243, N-3103 Toensberg (Norway); San Haisheng [Pen-Tung Sah Micro-Electro-Mechanical Systems Research Center, Xiamen University, Xiamen, Fujian 361005 (China)

2009-06-15T23:59:59.000Z

152

First-principles calculations of niobium hydride formation in superconducting radio-frequency cavities  

SciTech Connect (OSTI)

Niobium hydride is suspected to be a major contributor to degradation of the quality factor of niobium superconducting radio-frequency (SRF) cavities. In this study, we connect the fundamental properties of hydrogen in niobium to SRF cavity performance and processing. We modeled several of the niobium hydride phases relevant to SRF cavities and present their thermodynamic, electronic, and geometric properties determined from calculations based on density-functional theory. We find that the absorption of hydrogen from the gas phase into niobium is exothermic and hydrogen becomes somewhat anionic. The absorption of hydrogen by niobium lattice vacancies is strongly preferred over absorption into interstitial sites. A single vacancy can accommodate six hydrogen atoms in the symmetrically equivalent lowest-energy sites and additional hydrogen in the nearby interstitial sites affected by the strain field: this indicates that a vacancy can serve as a nucleation center for hydride phase formation. Small hydride precipitates may then occur near lattice vacancies upon cooling. Vacancy clusters and extended defects should also be enriched in hydrogen, potentially resulting in extended hydride phase regions upon cooling. We also assess the phase changes in the niobium-hydrogen system based on charge transfer between niobium and hydrogen, the strain field associated with interstitial hydrogen, and the geometry of the hydride phases. The results of this study stress the importance of not only the hydrogen content in niobium, but also the recovery state of niobium for the performance of SRF cavities.

Ford, Denise C.; Cooley, Lance D.; Seidman, David N.

2013-09-01T23:59:59.000Z

153

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

DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

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.

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

2012-04-01T23:59:59.000Z

154

Preface to Special Topic: Advances in Radio Frequency Physics in Fusion Plasmas  

SciTech Connect (OSTI)

It has long been recognized that auxiliary plasma heating will be required to achieve the high temperature, high density conditions within a magnetically confined plasma in which a fusion “burn” may be sustained by copious fusion reactions. Consequently, the application of radio and microwave frequency electromagnetic waves to magnetically confined plasma, commonly referred to as RF, has been a major part of the program almost since its inception in the 1950s. These RF waves provide heating, current drive, plasma profile control, and Magnetohydrodynamics (MHD) stabilization. Fusion experiments employ electromagnetic radiation in a wide range of frequencies, from tens of MHz to hundreds of GHz. The fusion devices containing the plasma are typically tori, axisymmetric or non, in which the equilibrium magnetic fields are composed of a strong toroidal magnetic field generated by external coils, and a poloidal field created, at least in the symmetric configurations, by currents flowing in the plasma. The waves are excited in the peripheral regions of the plasma, by specially designed launching structures, and subsequently propagate into the core regions, where resonant wave-plasma interactions produce localized heating or other modification of the local equilibrium profiles. Experimental studies coupled with the development of theoretical models and advanced simulation codes over the past 40+ years have led to an unprecedented understanding of the physics of RF heating and current drive in the core of magnetic fusion devices. Nevertheless, there are serious gaps in our knowledge base that continue to have a negative impact on the success of ongoing experiments and that must be resolved as the program progresses to the next generation devices and ultimately to “demo” and “fusion power plant.” A serious gap, at least in the ion cyclotron (IC) range of frequencies and partially in the lower hybrid frequency ranges, is the difficulty in coupling large amount of power to the plasma while minimizing the interaction between the plasma and launching structures. These potentially harmful interactions between the plasma and the vessel and launching structures are challenging: (i) significant and variable loss of power in the edge regions of confined plasmas and surrounding vessel structures adversely affect the core plasma performance and lifetime of a device; (ii) the launcher design is partly “trial and error,” with the consequence that launchers may have to be reconfigured after initial tests in a given device, at an additional cost. Over the broader frequency range, another serious gap is a quantitative lack of understanding of the combined effects of nonlinear wave-plasma processes, energetic particle interactions and non-axisymmetric equilibrium effects on determining the overall efficiency of plasma equilibrium and stability profile control techniques using RF waves. This is complicated by a corresponding lack of predictive understanding of the time evolution of transport and stability processes in fusion plasmas.

Tuccillo, Angelo A.; Ceccuzzi, Silvio [Unitŕ Tecnica Fusione ENEA, C. R. Frascati, 00044 RM (Italy); Phillips, Cynthia K. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

2014-06-15T23:59:59.000Z

155

Frequency domain transfer function identification using the computer program SYSFIT  

SciTech Connect (OSTI)

Because the primary application of SYSFIT for BPA involves studying power system dynamics, this investigation was geared toward simulating the effects that might be encountered in studying electromechanical oscillations in power systems. Although the intended focus of this work is power system oscillations, the studies are sufficiently genetic that the results can be applied to many types of oscillatory systems with closely-spaced modes. In general, there are two possible ways of solving the optimization problem. One is to use a least-squares optimization function and to write the system in such a form that the problem becomes one of linear least-squares. The solution can then be obtained using a standard least-squares technique. The other method involves using a search method to obtain the optimal model. This method allows considerably more freedom in forming the optimization function and model, but it requires an initial guess of the system parameters. SYSFIT employs this second approach. Detailed investigations were conducted into three main areas: (1) fitting to exact frequency response data of a linear system; (2) fitting to the discrete Fourier transformation of noisy data; and (3) fitting to multi-path systems. The first area consisted of investigating the effects of alternative optimization cost function options; using different optimization search methods; incorrect model order, missing response data; closely-spaced poles; and closely-spaced pole-zero pairs. Within the second area, different noise colorations and levels were studied. In the third area, methods were investigated for improving fitting results by incorporating more than one system path. The following is a list of guidelines and properties developed from the study for fitting a transfer function to the frequency response of a system using optimization search methods.

Trudnowski, D.J.

1992-12-01T23:59:59.000Z

156

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

SciTech Connect (OSTI)

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

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

2011-05-01T23:59:59.000Z

157

A high frequency radio study of G11.2-0.3, a historical supernova remnant with a flat spectrum core  

E-Print Network [OSTI]

We present radio maps of the historical supernova remnant G11.2-0.3 in the frequency range from 4.85 GHz to 32 GHz. The integrated spectrum with \\alpha = -0.50 (S ~ \

R. Kothes; W. Reich

2001-04-24T23:59:59.000Z

158

The Murchison Widefield Array: The Square Kilometre Array Precursor at Low Radio Frequencies  

E-Print Network [OSTI]

The Murchison Widefield Array (MWA) is one of three Square Kilometre Array Precursor telescopes and is located at the Murchison Radio-astronomy Observatory in the Murchison Shire of the mid-west of Western Australia, a ...

Goeke, Robert F.

159

HEATING THE HOT ATMOSPHERES OF GALAXY GROUPS AND CLUSTERS WITH CAVITIES: THE RELATIONSHIP BETWEEN JET POWER AND LOW-FREQUENCY RADIO EMISSION  

SciTech Connect (OSTI)

We present scaling relations between jet power and radio power measured using the Giant Metrewave Radio Telescope (GMRT), Chandra, and XMM-Newton, for a sample of nine galaxy groups combined with the BIrzan et al. sample of clusters. Cavity power is used as a proxy for mechanical jet power. Radio power is measured at 235 MHz and 1.4 GHz, and the integrated 10 MHz-10 GHz radio luminosity is estimated from the GMRT 610-235 MHz spectral index. The use of consistently analyzed, high-resolution low-frequency radio data from a single observatory makes the radio powers for the groups more reliable than those used by previous studies, and the combined sample covers 6-7 decades in radio power and 5 decades in cavity power. We find a relation of the form P{sub jet}{proportional_to} L{approx}0.7{sub radio} for integrated radio luminosity, with a total scatter of {sigma}{sub Lrad} = 0.63 and an intrinsic scatter of {sigma}{sub i,Lrad} = 0.59. A similar relation is found for 235 MHz power, but a slightly flatter relation with greater scatter is found for 1.4 GHz power, suggesting that low-frequency or broadband radio measurements are superior jet power indicators. We find our low-frequency relations to be in good agreement with previous observational results. Comparison with jet models shows reasonable agreement, which may be improved if radio sources have a significant low-energy electron population. We consider possible factors that could bias our results or render them more uncertain, and find that correcting for such factors in those groups we are able to study in detail leads to a flattening of the P{sub jet}:L{sub radio} relation.

O'Sullivan, E.; Raychaudhury, S.; Ponman, T. J. [School of Physics and Astronomy, University of Birmingham, Birmingham, B15 2TT (United Kingdom); Giacintucci, S.; David, L. P.; Gitti, M.; Vrtilek, J. M., E-mail: ejos@star.sr.bham.ac.uk [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2011-07-01T23:59:59.000Z

160

Slow Radio-Frequency Processing of Large Oil Shale Volumes to Produce Petroleum-Like Shale Oil  

SciTech Connect (OSTI)

A process is proposed to convert oil shale by radio frequency heating over a period of months to years to create a product similar to natural petroleum. Electrodes would be placed in drill holes, either vertical or horizontal, and a radio frequency chosen so that the penetration depth of the radio waves is of the order of tens to hundreds of meters. A combination of excess volume production and overburden compaction drives the oil and gas from the shale into the drill holes, where it is pumped to the surface. Electrical energy for the process could be provided initially by excess regional capacity, especially off-peak power, which would generate {approx}3 x 10{sup 5} bbl/day of synthetic crude oil, depending on shale grade. The electricity cost, using conservative efficiency assumptions, is $4.70 to $6.30/bbl, depending on grade and heating rate. At steady state, co-produced gas can generate more than half the electric power needed for the process, with the fraction depending on oil shale grade. This would increase production to 7.3 x 10{sup 5} bbl/day for 104 l/Mg shale and 1.6 x 10{sup 6} bbl/day for 146 l/Mg shale using a combination of off-peak power and power from co-produced gas.

Burnham, A K

2003-08-20T23:59:59.000Z

Note: This page contains sample records for the topic "radio frequency identification" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

VERY LONG BASELINE ARRAY MULTI-FREQUENCY POLARIMETRIC IMAGING OF RADIO-LOUD BROAD ABSORPTION LINE QUASARS  

SciTech Connect (OSTI)

We conducted the first multi-frequency polarimetric imaging of four broad absorption line (BAL) quasars using the Very Long Baseline Array at milliarcsecond resolutions to investigate the inclination of the nonthermal jet and test the hypothesis that radio sources in BAL quasars are still young. Among these four sources, J0928+446, J1018+0530, and J1405+4056 show one-sided structures in parsec scales and polarized emission detected in the core. These characteristics are consistent with those of blazars. We set constraints on viewing angles to <66 Degree-Sign for these jets in the framework of a Doppler beaming effect. J1159+0112 exhibits an unpolarized gigahertz-peaked spectrum component and several discrete blobs with steep spectra on both sides of the central component across {approx}1 kpc. These properties are consistent with those of young radio sources. We discuss the structures of jets and active galactic nucleus wind.

Hayashi, Takayuki J.; Nagai, Hiroshi [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo, 181-8588 (Japan); Doi, Akihiro, E-mail: t.hayashi@nao.ac.jp [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo, Sagamihara, Kanagawa, 252-5210 (Japan)

2013-07-20T23:59:59.000Z

162

LOW-FREQUENCY RADIO-FIR CORRELATION IN NORMAL GALAXIES AT {approx}1 kpc SCALES  

SciTech Connect (OSTI)

We study the radio-FIR correlation between the nonthermal (synchrotron) radio continuum emission at {lambda}90 cm (333 MHz) and the far-infrared emission due to cool ({approx}20 K) dust at {lambda}70 {mu}m in spatially resolved normal galaxies at scales of {approx}1 kpc. The slope of the radio-FIR correlation significantly differs between the arm and interarm regions. However, this change is not evident at a lower wavelength of {lambda}20 cm (1.4 GHz). We find the slope of the correlation in the arm to be 0.8 {+-} 0.12 and we use this to determine the coupling between equipartition magnetic field (B{sub eq}) and gas density ({rho}{sub gas}) as B{sub eq}{proportional_to}{rho}{sup 0.51{+-}0.12}{sub gas}. This is close to what is predicted by magnetohydrodynamic simulations of turbulent interstellar medium, provided the same region produces both the radio and far-infrared emission. We argue that at 1 kpc scales this condition is satisfied for radio emission at 1.4 GHz and may not be satisfied at 333 MHz. The change of slope observed in the interarm region could be caused by propagation of low energy ({approx}1.5 GeV) and long-lived ({approx}10{sup 8} yr) cosmic-ray electrons at 333 MHz.

Basu, Aritra; Roy, Subhashis; Mitra, Dipanjan, E-mail: aritra@ncra.tifr.res.in, E-mail: roy@ncra.tifr.res.in, E-mail: dmitra@ncra.tifr.res.in [National Center for Radio Astrophysics, TIFR, Pune University Campus, Ganeshkhind Road, Pune-411007 (India)

2012-09-10T23:59:59.000Z

163

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

E-Print Network [OSTI]

agile data transmission schemes employed by cognitive radio transceivers for use in dynamic spectrum for this apparent spectrum scarcity. Although, measurement studies have shown that licensed spectrum is relatively- This work was supported by NSF grants ANI-0230786 and ANI- 0335272. licensed users "borrowing" spectrum from

Kansas, University of

164

Etching of Niobium Sample Placed on Superconducting Radio Frequency Cavity Surface in Ar/CL2 Plasma  

SciTech Connect (OSTI)

Plasma based surface modification is a promising alternative to wet etching of superconducting radio frequency (SRF) cavities. It has been proven with flat samples that the bulk Niobium (Nb) removal rate and the surface roughness after the plasma etchings are equal to or better than wet etching processes. To optimize the plasma parameters, we are using a single cell cavity with 20 sample holders symmetrically distributed over the cell. These holders serve the purpose of diagnostic ports for the measurement of the plasma parameters and for the holding of the Nb sample to be etched. The plasma properties at RF (100 MHz) and MW (2.45 GHz) frequencies are being measured with the help of electrical and optical probes at different pressures and RF power levels inside of this cavity. The niobium coupons placed on several holders around the cell are being etched simultaneously. The etching results will be presented at this conference.

Janardan Upadhyay, Larry Phillips, Anne-Marie Valente

2011-09-01T23:59:59.000Z

165

assessing radio-isotope identification: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

will be provided by a combination of Cherenkov counters: a ring-imaging detector Physics Requirement 27 Collaboration Identification Physics Websites Summary: S , ,...

166

The design and construction of a 130 K.V. radio frequency Cockcroft Walton type generator  

E-Print Network [OSTI]

83 - Ohaite 300 oha Parasitic Hesistors CR4 ?8 turns Mo. 18 wire, $/16" dia /I Ii Q GH CH ~ 2+$ MH 100 Mil 6 CR - 17 turns Mo. 18 wire wound on 1 watt 1 negoha resistor Tl 2(00 0 2500 Volt k. C. Power Tranefozaer 600 Mil, T2 T Poser Filter... Crasffy Conptonp 14Tep and Vsn M'tap Phg%? ReYe lpga Q9 (1933) Bouwerse i. ~ and Xundte L. ?, Xeits f. Tech, Physi@ ll~ 209 (1937) Lorraing P. , Rev. Sci. Inst 20c 216 (1949) Terssn, Radio Engineers Handbook 6 Ha13e K 1 ~ Bcr. Stand's Tech. Payer...

Robba, William Augustus

1951-01-01T23:59:59.000Z

167

New Architectures for Radio-Frequency DC-DC Power Conversion  

E-Print Network [OSTI]

This document proposes two new architectures for switched-mode dc–dc power conversion. The proposed architectures enable dramatic increases in switching frequency to be realized while preserving features critical in practice, ...

Rivas, Juan M.

168

Analyzing the use of radio frequency identification (RFID) on the container industry  

E-Print Network [OSTI]

After the terrorist attacks of 9/11 US realized the importance of building and maintaining a secure environment that would protect US borders. The significance of having a secure supply chain in the US is apparent, since ...

Panagopoulos, Nikolaos-Stavros

2007-01-01T23:59:59.000Z

169

Mitigating container security risk using real-time monitoring with active Radio Frequency Identification and sensors  

E-Print Network [OSTI]

The global village in which we live enables increased trade and commerce across regions but also brings a complicated new set of challenges such as terrorist activity, human and drug smuggling and theft in foreign or ...

Schlesinger, Adam Ian

2005-01-01T23:59:59.000Z

170

ARG-US RADIO FREQUENCY IDENTIFICATION (RFID) Technology (IN-08-046) -  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLasDelivered‰PNGExperience4AJ01) (See95TI07)Operations2AP-XPSAPS50 -Issue 60ARCS - Access

171

Probing the Climatological Impact of a Cosmic Ray-Cloud Connection through Low-Frequency Radio Observations  

E-Print Network [OSTI]

It has been proposed that cosmic ray events could have a causal relationship with cloud formation rates. Given the weak constraints on the role that cloud formation plays in climate forcing it is essential to understand the role such a relationship could have in shaping the Earth's climate. This issue has been previously investigated in the context of the long-term effect of cosmic ray events on climate. However, in order to establish whether or not such a relationship exists, measurements of short-timescale solar events, individual cosmic ray events, and spatially correlated cloud parameters could be of great significance. Here we propose such a comparison using observations from a pair of radio telescopes arrays, the Long Wavelength Array (LWA) and the Eight-meter-wavelength Transient Array (ETA). These low-frequency radio arrays have a unique ability to simultaneously conduct solar, ionospheric and cosmic rays observations and are thus ideal for such a comparison. We will outline plans for a comparison usi...

Magee, Nathan

2011-01-01T23:59:59.000Z

172

Faint Radio Sources in the NOAO Bootes Field. VLBA Imaging and Optical Identifications  

E-Print Network [OSTI]

As a step toward investigating the parsec-scale properties of faint extragalactic radio sources, the Very Long Baseline Array (VLBA) was used at 5.0 GHz to obtain phase-referenced images of 76 sources in the NOAO Bootes field. These 76 sources were selected from the FIRST catalog to have peak flux densities above 10 mJy at 5 arcsec resolution and deconvolved major diameters of less than 3 arcsec at 1.4 GHz. Fifty-seven of these faint radio sources were identified with accretion-powered radio galaxies and quasars brighter than 25.5 mag in the optical I band. On VLA scales at 1.4 GHz, a measure of the compactness of the faint sources (the ratio of the peak flux density from FIRST to the integrated flux density from the NVSS catalog) spans the full range of possibilites arising from source-resolution effects. Thirty of the faint radio sources, or 39 +9/-7%, were detected with the VLBA at 5.0 GHz with peak flux densities above 6 sigma ~2 mJy at 2 mas resolution. The VLBA detections occur through the full range of compactness ratios. The stronger VLBA detections can themselves serve as phase-reference calibrators, boding well for opening up much of the radio sky to VLBA imaging. For the adopted cosmology, the VLBA resolution correponds to 17 pc or finer. Most VLBA detections are unresolved or slightly resolved but one is diffuse and five show either double or core-jet structures; the properties of these latter six are discussed in detail. Three VLBA detections are unidentified and fainter than 25.5 mag in the optical I band; their properties are highlighted because they likely mark optically-obscured active nuclei at high redshift.

J. M. Wrobel; G. B. Taylor; T. A. Rector; S. T. Myers; C. D. Fassnacht

2005-06-09T23:59:59.000Z

173

Experimental measurements in a radio frequency discharge heated supersonic flow: Evaluation of a potential electric propulsion thruster  

SciTech Connect (OSTI)

An operational radio frequency discharge-driven supersonic flow system, which utilizes an inductively and capacitively coupled plasma (ICCP) tube to produce high enthalpy source gas, is described. The ICCP coupled to a properly designed nozzle represents a potential electric propulsion device. The high gas temperatures achieved in the plasma discharge (> 5000 K) and the electrodeless nature of the tube's operation offers potentially high thruster performance coupled and long operational lifetime. A preliminary characterization of the current system was established using emission and probe-based measurements. A nominal peak specific impulse of 155 s was estimated for operation with argon. The calculated thrust based upon the peak velocity and mass flow through the device is 1.1 N. 14 refs., 10 figs.

Wantuck, P.J.; Hull, D.E.

1991-01-01T23:59:59.000Z

174

High quality single shot ultrafast MeV electron diffraction from a photocathode radio-frequency gun  

SciTech Connect (OSTI)

A compact ultrafast electron diffractometer, consisting of an s-band 1.6 cell photocathode radio-frequency gun, a multi-function changeable sample chamber, and a sensitive relativistic electron detector, was built at Shanghai Jiao Tong University. High-quality single-shot transmission electron diffraction patterns have been recorded by scattering 2.5?MeV electrons off single crystalline gold and polycrystalline aluminum samples. The high quality diffraction pattern indicates an excellent spatial resolution, with the ratio of the diffraction ring radius over the ring rms width beyond 10. The electron pulse width is estimated to be about 300 fs. The high temporal and spatial resolution may open new opportunities in various areas of sciences.

Fu, Feichao; Liu, Shengguang; Zhu, Pengfei; Xiang, Dao, E-mail: dxiang@sjtu.edu.cn; Zhang, Jie, E-mail: jzhang1@sjtu.edu.cn [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Cao, Jianming [Department of Physics and National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310 (United States)

2014-08-15T23:59:59.000Z

175

Reduced leakage in epitaxial BiFeO{sub 3} films following oxygen radio frequency plasma treatment  

SciTech Connect (OSTI)

Epitaxial BiFeO{sub 3} (BFO) films were deposited using pulsed laser deposition method. The prepared films were characterized using x-ray diffraction, x-ray reflectivity, ferroelectric loop tracer, and leakage current measurements before and after oxygen plasma treatment. The leakage current of the films, a crucial parameter in device applications, is observed to be reduced by two orders of magnitude with oxygen plasma treatment at room temperature. P-E hysteresis loops were observed in oxygen plasma treated BFO films. The observed results indicate the usefulness of oxygen radio frequency plasma treatment (RF 13.56 MHz), which is an effective and low temperature processing technique, in such lossy ferroelectric thin films.

Kothari, Deepti [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India) [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India); UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452 017 (India); Upadhyay, Sanjay K.; Raghavendra Reddy, V. [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452 017 (India)] [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452 017 (India); Jariwala, C.; Raole, P. M. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)] [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)

2013-06-07T23:59:59.000Z

176

Radio frequency accelerating cavity having slotted irises for damping certain electromagnetic modes  

DOE Patents [OSTI]

An accelerating cavity is disclosed having one or more iris structures mounted therein for strongly damping unwanted frequencies that are generated in the cavity by bunches of particles in a particle beam that is accelerated through the cavity during its operation. Each of the iris structures is characterized by containing a plurality of radial slots therein that extend from the central aperture through the iris member to the perimeter thereof. The outer end of each of the radial slots includes an enlarged portion that is effective to prevent undesired frequencies from being reflected back into the center aperture of the iris member. Waveguide means connect the outer ends of the radial slots to frequency damping means or to a dump or dumps. 17 figures.

Palmer, R.B.

1991-05-21T23:59:59.000Z

177

Radio frequency accelerating cavity having slotted irises for damping certain electromagnetic modes  

DOE Patents [OSTI]

An accelerating cavity having one or more iris structures mounted therein for strongly damping unwanted frequencies that are generated in the cavity by bunches of particles in a particle beam that is accelerated through the cavity during its operation. Each of the iris structures is characterized by containing a plurality of radial slots therein that extend from the central aperture through the iris member to the perimeter thereof. The outer end of each of the radial slots includes an enlarged portion that is effective to prevent undesired frequencies from being reflected back into the center aperture of the iris member. Waveguide means connect the outer ends of the radial slots to frequency damping means or to a dump or dumps.

Palmer, Robert B. (Shoreham, NY)

1991-01-01T23:59:59.000Z

178

Implementation of a Dual Containment/Surveillance System utilizing scene-change detection and radio frequency technology  

SciTech Connect (OSTI)

This paper will examine the implementation of scene-change detection and radio frequency technology within a Dual Containment/Surveillance (C/S) System. Additionally, this paper will examine the human performance factors in the operation of these systems. Currently, Westinghouse Savannah River Company utilizes the Continuous Item Monitoring and Surveillance System (CIMS) in the performance of Dual C/S to monitor special nuclear materials within International Atomic Energy Agency (IAEA) Safeguards and Domestic Safeguards. CIMS is comprised of the Material Monitoring System (MMS) (R), a multi-media electronic surveillance system developed by Sandia National Laboratory which incorporates the use of active seals commonly called Radio Frequency Tamper Indicating Devices (RFTIDs), NT Vision (R) as developed by Los Alamos National Laboratory, a Microsoft Windows NT (R) based operating system providing for domestic scene-change detection and the Digital Multi-Camera Optical Surveillance System (DMOS) (R) which provides scene-change detection for IAEA. Although this paper will focus on the implementation of Dual C/S utilizing the Continuous Item Monitoring and Surveillance System, the necessity for a thorough review of Safeguards and Security requirements with organizations and personnel having minimal to no prior MPC&A training will also be covered. Successful Dual C/S implementation plans must consider not only system design and failure modes, but must also be accompanied with the appropriate ''mind shift'' within operations and technical personnel. This is required to ensure completion of both physical and electronic activities, and system design changes are performed conscientiously and with full awareness of MPC&A requirements.

FITZGERALD, ERIC; KOENIG, RICHARD

2005-06-27T23:59:59.000Z

179

A METHOD TO EXTRACT THE ANGULAR POWER SPECTRUM OF THE EPOCH OF REIONIZATION FROM LOW-FREQUENCY RADIO INTERFEROMETERS  

SciTech Connect (OSTI)

The redshifted 21 cm signal of neutral hydrogen from the epoch of reionization (EoR) is extremely weak and its first detection is therefore expected to be statistical with first-generation low-frequency radio interferometers. In this Letter, we propose a method to extract the angular power spectrum of the EoR from the visibility correlation coefficients p{sub ij} (u, v), instead of the visibilities V{sub ij} (u, v) measured directly by radio interferometers in conventional algorithm. The visibility correlation coefficients are defined as p{sub ij}(u,v)=V{sub ij}(u,v)/{radical}(|V{sub ii}||V{sub jj}|) by introducing the autocorrelation terms V{sub ii} and V{sub jj} such that the angular power spectrum C{sub l} can be obtained through C{sub l} = T {sup 2}{sub 0}(|p{sub ij} (u, v)|{sup 2}), independently of the primary beams of antennas. This also partially removes the influence of receiver gains in the measurement of C{sub l} because the amplitudes of the gains cancel each other out in the statistical average operation of (|p{sub ij} (u, v)|{sup 2}). We use the average system temperature T{sub 0} as a calibrator of C{sub l}, which is dominated by the Milky Way and extragalactic sources in the frequency range that we are interested in, below 200 MHz. Finally, we demonstrate the feasibility of this novel method using the simulated sky maps as targets and the 21 CentiMeter Array (21CMA) as interferometer.

Zheng Qian; Wu Xiangping; Gu Junhua [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Wang Jingying; Xu Haiguang [Department of Physics, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China)

2012-10-10T23:59:59.000Z

180

Method and apparatus for powering an electrodeless lamp with reduced radio frequency interference  

DOE Patents [OSTI]

An electrodeless lamp waveguide structure includes tuned absorbers for spurious RF signals. A lamp waveguide with an integral frequency selective attenuation includes resonant absorbers positioned within the waveguide to absorb spurious out-of-band RF energy. The absorbers have a negligible effect on energy at the selected frequency used to excite plasma in the lamp. In a first embodiment, one or more thin slabs of lossy magnetic material are affixed to the sidewalls of the waveguide at approximately one quarter wavelength of the spurious signal from an end wall of the waveguide. The positioning of the lossy material optimizes absorption of power from the spurious signal. In a second embodiment, one or more thin slabs of lossy magnetic material are used in conjunction with band rejection waveguide filter elements. In a third embodiment, one or more microstrip filter elements are tuned to the frequency of the spurious signal and positioned within the waveguide to couple and absorb the spurious signal's energy. All three embodiments absorb negligible energy at the selected frequency and so do not significantly diminish the energy efficiency of the lamp.

Simpson, James E. (Gaithersburg, MD)

1999-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "radio frequency identification" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Method and apparatus for powering an electrodeless lamp with reduced radio frequency interference  

DOE Patents [OSTI]

An electrodeless lamp waveguide structure includes tuned absorbers for spurious RF signals. A lamp waveguide with an integral frequency selective attenuation includes resonant absorbers positioned within the waveguide to absorb spurious out-of-band RF energy. The absorbers have a negligible effect on energy at the selected frequency used to excite plasma in the lamp. In a first embodiment, one or more thin slabs of lossy magnetic material are affixed to the sidewalls of the waveguide at approximately one quarter wavelength of the spurious signal from an end wall of the waveguide. The positioning of the lossy material optimizes absorption of power from the spurious signal. In a second embodiment, one or more thin slabs of lossy magnetic material are used in conjunction with band rejection waveguide filter elements. In a third embodiment, one or more microstrip filter elements are tuned to the frequency of the spurious signal and positioned within the waveguide to couple and absorb the spurious signal's energy. All three embodiments absorb negligible energy at the selected frequency and so do not significantly diminish the energy efficiency of the lamp. 18 figs.

Simpson, J.E.

1999-06-08T23:59:59.000Z

182

PHYSICAL REVIEW B VOLUME 48, NUMBER 13 1 OCTOBER 1993-1 Determination of the absolute sign of nuclear quadrupole interactions by laser radio-frequency  

E-Print Network [OSTI]

PHYSICAL REVIEW B VOLUME 48, NUMBER 13 1 OCTOBER 1993-1 Determination of the absolute sign of nuclear quadrupole interactions by laser radio-frequency double-resonance experiments Tilo Blasberg the quadrupole moment of nuclear spins I > + with the electric-field-gradient (EFG) tensor leads to a splitting

Suter, Dieter

183

Challenges and opportunities for multi-functional oxide thin films for voltage tunable radio frequency/microwave components  

SciTech Connect (OSTI)

There has been significant progress on the fundamental science and technological applications of complex oxides and multiferroics. Among complex oxide thin films, barium strontium titanate (BST) has become the material of choice for room-temperature-based voltage-tunable dielectric thin films, due to its large dielectric tunability and low microwave loss at room temperature. BST thin film varactor technology based reconfigurable radio frequency (RF)/microwave components have been demonstrated with the potential to lower the size, weight, and power needs of a future generation of communication and radar systems. Low-power multiferroic devices have also been recently demonstrated. Strong magneto-electric coupling has also been demonstrated in different multiferroic heterostructures, which show giant voltage control of the ferromagnetic resonance frequency of more than two octaves. This manuscript reviews recent advances in the processing, and application development for the complex oxides and multiferroics, with the focus on voltage tunable RF/microwave components. The over-arching goal of this review is to provide a synopsis of the current state-of the-art of complex oxide and multiferroic thin film materials and devices, identify technical issues and technical challenges that need to be overcome for successful insertion of the technology for both military and commercial applications, and provide mitigation strategies to address these technical challenges.

Subramanyam, Guru, E-mail: gsubramanyam1@udayton.edu [Department of Electrical and Computer Engineering, University of Dayton, Dayton, Ohio 45469 (United States); Cole, M. W., E-mail: melanie.w.cole.civ@mail.mil [U.S. Army Research Laboratory, Weapons and Materials Research Directorate, Aberdeen Proving Ground, Maryland 21005 (United States); Sun, Nian X. [Department of Electrical and Computer Engineering, Northeastern University, Boston, Massachusetts 02115 (United States); Kalkur, Thottam S. [Department of Electrical and Computer Engineering, University of Colorado, Colorado Springs, Colorado 80918 (United States); Sbrockey, Nick M.; Tompa, Gary S. [Structured Materials Industries, Inc., Piscataway, New Jersey 08854 (United States); Guo, Xiaomei [Boston Applied Technologies, Inc., Woburn, Massachusetts 01801 (United States); Chen, Chonglin [Department of Physics and Astronomy, University of Texas, San Antonio, Texas 78249 (United States); Alpay, S. P.; Rossetti, G. A. [Institute of Materials Science and Materials Science and Engineering Program, University of Connecticut, Storrs, Connecticut 06269 (United States); Dayal, Kaushik [Mechanics, Materials and Computing, Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Chen, Long-Qing [Department of Materials Science and Engineering, Penn State University, University Park, Pennsylvania 16802 (United States); Schlom, Darrell G. [Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853 (United States); Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853 (United States)

2013-11-21T23:59:59.000Z

184

Implementation guidance for industrial-level security systems using radio frequency alarm links  

SciTech Connect (OSTI)

Spread spectrum (SS) RF transmission technologies have properties that make the transmitted signal difficult to intercept, interpret, and jam. The digital code used in the modulation process results in a signal that has high reception reliability and supports multiple use of frequency bands and selective addressing. These attributes and the relatively low installation cost of RF systems make SSRF technologies candidate for communications links in security systems used for industrial sites, remote locations, and where trenching or other disturbances of soil or structures may not be desirable or may be costly. This guide provides a description of such a system and presents implementation methods that may be of engineering benefit.

Swank, R.G.

1996-07-12T23:59:59.000Z

185

A Task-level Model for Optomotor Yaw Regulation in Drosophila Melanogaster: A Frequency-Domain System Identification Approach  

E-Print Network [OSTI]

-level locomotor behavior to a single-input­single-output system [4]­[6]. Optomotor yaw regulation has been studiedA Task-level Model for Optomotor Yaw Regulation in Drosophila Melanogaster: A Frequency-Domain System Identification Approach Eatai Roth1, Michael B. Reiser2, Michael H. Dickinson3, and Noah J. Cowan1

186

1 | P a g e Summary of Fish-Barge Interaction Research and Fixed Dual Frequency Identification Sonar  

E-Print Network [OSTI]

1 | P a g e Summary of Fish-Barge Interaction Research and Fixed Dual Frequency Identification of Engineers (USACE) and the U.S. Fish and Wildlife Service (USFWS) have conducted laboratory and field in the Chicago Sanitary and Ship Canal (CSSC) and the resulting impacts to fish behavior. The experiments

US Army Corps of Engineers

187

THE Low-level Radio Frequency System for the superconducting cavities of National Synchrotron Light Source II  

SciTech Connect (OSTI)

A digital low-level radio frequency (LLRF) field controller has been developed for the storage ring of The National Synchrotron Light Source-II (NSLS-II). The primary performance goal for the LLRF is to support the required RF operation of the superconducting cavities with a beam current of 500mA and a 0.14 degree or better RF phase stability. The digital field controller is FPGA-based, in a standard format 19-inch/I-U chassis. It has an option of high-level control support with MATLAB running on a local host computer through a USB2.0 port. The field controller has been field tested with the high-power superconducting RF (SRF) at Canadian light Source, and successfully stored a high beam current of 250 mA. The test results show that required specifications for the cavity RF field stability are met. This digital field controller is also currently being used as a development platform for other functional modules in the NSLS-II RF systems.

Ma, H.; Rose, J.; Holub, B.; Cupolo, J.; Oliva, J.; Sikora, R.; Yeddulla, M.

2011-03-28T23:59:59.000Z

188

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

SciTech Connect (OSTI)

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)] 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.

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

2013-02-01T23:59:59.000Z

189

Radio frequency phototube  

DOE Patents [OSTI]

A method and apparatus of obtaining a record of repetitive optical or other phenomena having durations in the picosecond range, comprising a circular scan electron tube to receive light pulses and convert them to electron images consisting with fast nanosecond electronic signals, a continuous wave light or other particle pulses, e.g. electron picosecond pulses, and a synchronizing mechanism arranged to synchronize the deflection of the electron image (images) in the tube (tubes) with the repetition rate of the incident pulse train. There is also provided a method and apparatus for digitization of a repetitive and random optical waveform with a bandwidth higher than 10 GHz.

Margaryan, Amur (Yerevan, AM); Gynashyan, Karlen (Yerevan, AM); Hashimoto, Osamu (Sendai, JP); Majewski, Stanislaw (Morgantown, WV); Tang, Linguang (Yorktown, VA); Marikyan, Gagik (Yerevan, AM); Marikyan, legal representative, Lia (Yerevan, AM)

2012-03-20T23:59:59.000Z

190

A frequency scanning method for the identification of harmonic instabilities in HVDC systems  

SciTech Connect (OSTI)

A Frequency Scanning Method is introduced in the paper to obtain a more accurate frequency characteristic for identifying harmonic instability in HVdc systems. An example of the application is used to identify the resonance frequencies in the CIGRE benchmark model. The paper shows that the Benchmark model is not tuned to the resonance frequency that it was designed for. Using the scanning method, the resonance frequency of the benchmark model may be shifted to demonstrate a simulation of core-saturation type instability.

Jiang, X.; Gole, A.M. [Univ. of Manitoba, Winnipeg, Manitoba (Canada). Dept. of Electrical and Computer Engineering] [Univ. of Manitoba, Winnipeg, Manitoba (Canada). Dept. of Electrical and Computer Engineering

1995-10-01T23:59:59.000Z

191

2-dimensional ion velocity distributions measured by laser-induced fluorescence above a radio-frequency biased silicon wafer  

E-Print Network [OSTI]

. Defining xrf ÂĽ 2p=srf and xion ÂĽ 2p=sion, the ratio of these two frequencies, xrf =xion, is an important parameter controlling ion dynamics in the sheath. For low frequency biases (xrf =xion ( 1), the transit of the bimodal distribution, DEi, decreases. At high fre- quencies (xrf =xion ) 1) DEi ! 0 and the IED converges

California at Los Angles, University of

192

The effect of secondary electrons on the separate control of ion energy and flux in dual-frequency capacitively coupled radio frequency discharges  

SciTech Connect (OSTI)

Dual-frequency capacitive discharges are used to separately control the mean ion energy, {epsilon}{sub ion}, and flux, {Gamma}{sub ion}, at the electrodes. We study the effect of secondary electrons on this separate control in argon discharges driven at 2+27 MHz at different pressures using Particle in Cell simulations. For secondary yield {gamma}{approx_equal}0, {Gamma}{sub ion} decreases as a function of the low frequency voltage amplitude due to the frequency coupling, while it increases at high {gamma} due to the effective multiplication of secondary electrons inside the sheaths. Therefore, separate control is strongly limited. {epsilon}{sub ion} increases with {gamma}, which might allow an in situ determination of {gamma}-coefficients.

Donko, Z.; Hartmann, P.; Korolov, I. [Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Schulze, J. [Research Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest (Hungary); Institute for Plasma and Atomic Physics, Ruhr-University Bochum, 44801 Bochum (Germany); Czarnetzki, U.; Schuengel, E. [Institute for Plasma and Atomic Physics, Ruhr-University Bochum, 44801 Bochum (Germany)

2010-08-23T23:59:59.000Z

193

A self-consistent global model of solenoidal-type inductively coupled plasma discharges including the effects of radio-frequency bias power  

SciTech Connect (OSTI)

We developed a self-consistent global simulator of solenoidal-type inductively coupled plasma discharges and observed the effect of the radio-frequency (rf) bias power on the plasma density and the electron temperature. We numerically solved a set of spatially averaged fluid equations for charged particles, neutrals, and radicals. Absorbed power by electrons is determined by using an analytic electron heating model including the anomalous skin effect. To analyze the effects of rf bias power on the plasma properties, our model also combines the electron heating and global transport modules with an rf sheath module in a self-consistent manner. The simulation results are compared with numerical results by using the commercial software package cfd-ace + (ESI group) and experimental measurements by using a wave cutoff probe and a single Langmuir probe.

Kwon, D. C.; Chang, W. S.; Song, M. Y.; Yoon, J.-S. [Convergence Plasma Research Center, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Park, M. [Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of); You, D. H. [Kyoungwon Tech, Inc., Seongnam 462-806 (Korea, Republic of); You, S. J. [Center for Vacuum Technology, Korea Research Institute of Standard and Science, Daejeon 305-340 (Korea, Republic of); Im, Y. H. [Division of Chemical Engineering, Chonbuk National University, Jeonju 561-756 (Korea, Republic of)

2011-04-01T23:59:59.000Z

194

Langmuir probes for SPIDER (source for the production of ions of deuterium extracted from radio frequency plasma) experiment: Tests in BATMAN (Bavarian test machine for negative ions)  

SciTech Connect (OSTI)

A prototype system of the Langmuir probes for SPIDER (Source for the production of Ions of Deuterium Extracted from RF plasma) was manufactured and experimentally qualified. The diagnostic was operated in RF (Radio Frequency) plasmas with cesium evaporation on the BATMAN (BAvarian Test MAchine for Negative ions) test facility, which can provide plasma conditions as expected in the SPIDER source. A RF passive compensation circuit was realised to operate the Langmuir probes in RF plasmas. The sensors’ holder, designed to better simulate the bias plate conditions in SPIDER, was exposed to a severe experimental campaign in BATMAN with cesium evaporation. No detrimental effect on the diagnostic due to cesium evaporation was found during the exposure to the BATMAN plasma and in particular the insulation of the electrodes was preserved. The paper presents the system prototype, the RF compensation circuit, the acquisition system (as foreseen in SPIDER), and the results obtained during the experimental campaigns.

Brombin, M., E-mail: matteo.brombin@igi.cnr.it; Spolaore, M.; Serianni, G.; Pomaro, N.; Taliercio, C.; Palma, M. Dalla; Pasqualotto, R. [Consorzio RFX, Corso Stati Uniti 4, I-35127 Padova (Italy); Schiesko, L. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany)

2014-11-15T23:59:59.000Z

195

Absolute atomic oxygen and nitrogen densities in radio-frequency driven atmospheric pressure cold plasmas: Synchrotron vacuum ultra-violet high-resolution Fourier-transform absorption measurements  

SciTech Connect (OSTI)

Reactive atomic species play a key role in emerging cold atmospheric pressure plasma applications, in particular, in plasma medicine. Absolute densities of atomic oxygen and atomic nitrogen were measured in a radio-frequency driven non-equilibrium plasma operated at atmospheric pressure using vacuum ultra-violet (VUV) absorption spectroscopy. The experiment was conducted on the DESIRS synchrotron beamline using a unique VUV Fourier-transform spectrometer. Measurements were carried out in plasmas operated in helium with air-like N{sub 2}/O{sub 2} (4:1) admixtures. A maximum in the O-atom concentration of (9.1 {+-} 0.7) Multiplication-Sign 10{sup 20} m{sup -3} was found at admixtures of 0.35 vol. %, while the N-atom concentration exhibits a maximum of (5.7 {+-} 0.4) Multiplication-Sign 10{sup 19} m{sup -3} at 0.1 vol. %.

Niemi, K.; O'Connell, D.; Gans, T. [York Plasma Institute, Department of Physics, University of York, York YO10 5DD (United Kingdom); Oliveira, N. de; Joyeux, D.; Nahon, L. [Synchrotron Soleil, l'Orme des Merisiers, St. Aubin BP 48, 91192 Gif sur Yvette Cedex (France); Booth, J. P. [Laboratoire de Physique des Plasmas-CNRS, Ecole Polytechnique, 91128 Palaiseau (France)

2013-07-15T23:59:59.000Z

196

An analysis of technical, process and organizational challenges confronting corporations implementing Radio Frequency Identification (RFID) technology projects  

E-Print Network [OSTI]

The purpose of the thesis is to identify practical challenges that are being addressed by companies implementing RFID related technologies in a variety of supply chain management applications. The test engagements undertaken ...

Roost, Nathan Christopher, 1975-

2004-01-01T23:59:59.000Z

197

On The Behaviour of Linear Dipole Antennas with Application to Passive Radio Frequency Identification Tags Operating at 869 MHz  

E-Print Network [OSTI]

distributions and read ranges. Also presented are modified dipole structures for optimising the electromagnetic energy launched by the reader. Data for the study are calculated using CST microwave studio which applies. Introduction. The current electronic product code (EPC) initiatives support a global deployment of RFID

Haddadi, Hamed

198

Abstract--Radio-frequency identification has a great number of unfulfilled prospects. Part of the problem until now has been  

E-Print Network [OSTI]

, The University of Hong Kong; PR China. (email: gqhuang@hku.hk). Rajit Gadh is the Director of the Wireless

California at Los Angeles, University of

199

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

SciTech Connect (OSTI)

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.

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)

2014-02-17T23:59:59.000Z

200

Radio and near-infrared observations of the steep spectrum Galactic plane radio source WKB 0314+57.8  

E-Print Network [OSTI]

Radio and near-infared observations towards the steep spectrum Galactic plane radio source WKB 0314+57.8 are presented, in order to clarify the nature of this source. The radio observations include archival and survey data, together with new Giant Metrewave Radio Telescope observations at 617 MHz. The near-infrared observations are in the J and K bands, from the Gemini instrument on the Shane 3-m telescope. The radio observations show that WKB 0314+57.8 is extended, with an very steep spectrum (with flux density proportional to frequency to -2.5 power between 40 MHz and 1.5 GHz). The colour--magnitude diagram constructed from near-infrared observations of the field suggests the presence of a z approx 0.08 galaxy cluster behind the Galactic plane, reddened by about 6 magnitudes of visual extinction. Although the steep spectrum source has no obvious identification, two other radio sources in the field covered by the near-infrared observations have tentative identifications with galaxies. These observations indicate that WKB 0314+57.8 is a relic source in a cluster of galaxies, not a pulsar.

D. A. Green; M. Lacy; S. Bhatnagar; E. L. Gates; P. J. Warner

2004-08-06T23:59:59.000Z

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201

Direct-current effects on magnetization reversal properties of submicron-size permalloy patterns for radio-frequency devices.  

SciTech Connect (OSTI)

Ferromagnetic resonance (FMR) spectroscopy is used to measure direct-current (dc) effects on the magnetization reversal properties of submicron-sized lateral patterned magnetic material. The observed FMR frequency-field relationship shows that for both 240 and 550 nm wide Permalloy (Py) nanowires the coercivity is reduced by {approx}33% when a 50 mA dc passes through the transmission line where the nanowires are incorporated. The temperature dependence of the coercivity has a {radical}T relationship which suggests the coherent rotation mode tendency in such 100 nm thick Py nanowires.

Zhang, H.; Hoffmann, A.; Divan, R.; Wang, P.; Clemson Univ.

2009-01-01T23:59:59.000Z

202

CRAF Handbook for Radio Astronomy  

E-Print Network [OSTI]

CRAF Handbook for Radio Astronomy EUROPEAN SCIENCE FOUNDATION Committee on Radio Astronomy forum for science. The ESF Expert Committee on Radio Astronomy Frequencies, CRAF, was established Astronomy Service and other passive applications. Cover: The 76-m diameter Lovell Telescope at Jodrell Bank

Rodriguez, Luis F.

203

Influence of growth temperature on electrical, optical, and plasmonic properties of aluminum:zinc oxide films grown by radio frequency magnetron sputtering  

SciTech Connect (OSTI)

We have investigated the responsible mechanism for the observation of metallic conductivity at room temperature and metal-semiconductor transition (MST) at lower temperatures for aluminum-doped zinc oxide (AZO) films. AZO films were grown on glass substrates by radio-frequency magnetron sputtering with varying substrate temperatures (T{sub s}). The films were found to be crystalline with the electrical resistivity close to 1.1 × 10{sup ?3} ? cm and transmittance more than 85% in the visible region. The saturated optical band gap of 3.76 eV was observed for the sample grown at T{sub s} of 400 °C, however, a slight decrease in the bandgap was noticed above 400 °C, which can be explained by Burstein–Moss effect. Temperature dependent resistivity measurements of these highly conducting and transparent films showed a MST at ?110 K. The observed metal-like and metal-semiconductor transitions are explained by taking into account the Mott phase transition and localization effects due to defects. All AZO films demonstrate crossover in permittivity from positive to negative and low loss in the near-infrared region, illustrating its applications for plasmonic metamaterials, including waveguides for near infrared telecommunication region. Based on the results presented in this study, the low electrical resistivity and high optical transmittance of AZO films suggested a possibility for the application in the flexible electronic devices, such as transparent conducting oxide film on LEDs, solar cells, and touch panels.

Dondapati, Hareesh; Santiago, Kevin; Pradhan, A. K. [Center for Materials Research, Norfolk State University, 700 Park Avenue, Norfolk, Virginia 23504 (United States)] [Center for Materials Research, Norfolk State University, 700 Park Avenue, Norfolk, Virginia 23504 (United States)

2013-10-14T23:59:59.000Z

204

Observation of radio frequency ring-shaped hollow cathode discharge plasma with MgO and Al electrodes for plasma processing  

SciTech Connect (OSTI)

Various high-density plasma sources have been proposed for plasma processing. Especially, the hollow cathode discharge is one of the powerful ones. In this work, radio-frequency (RF) driven ring-shaped hollow cathode discharges with high secondary-electron emission have been investigated, using an aluminum (Al) cathode, coated or not with magnesium oxide (MgO). The thickness of MgO thin film is approximately 200?nm. The RF discharge voltage for the coated cathode is almost the same as that for the uncoated one, in a wide range of Ar gas pressure, from 5.3 to 53.2?Pa. The results reveal that the plasma density has a peak at an Ar gas pressure of 10.6?Pa for both cathodes. The plasma density for the coated cathode is about 1.5–3 times higher than that for the uncoated one, at various gas pressures. To the contrary, the electron temperature for the coated cathode is lower than temperature obtained with the uncoated cathode, at various gas pressures. Radial profiles of electron saturation current, which is proportional to plasma flux, are also examined for a wide range of gas pressure. Radial profiles of electron temperature at various axial positions are almost uniform for both cathodes so that the diffusion process due to density gradient is dominant for plasma transport. The secondary electrons emitted from the coated cathode contribute to the improvement of the plasma flux radial profile obtained using the uncoated cathode.

Ohtsu, Yasunori, E-mail: ohtsuy@cc.saga-u.ac.jp; Matsumoto, Naoki [Department of Electrical and Electronic Engineering, Graduate School of Science and Engineering, Saga University, 1 Honjo-machi, Saga 840-8502 (Japan)

2014-05-15T23:59:59.000Z

205

Characteristics of high-purity Cu thin films deposited on polyimide by radio-frequency Ar/H{sub 2} atmospheric-pressure plasma jet  

SciTech Connect (OSTI)

With a view to fabricating future flexible electronic devices, an atmospheric-pressure plasma jet driven by 13.56 MHz radio-frequency power is developed for depositing Cu thin films on polyimide, where a Cu wire inserted inside the quartz tube was used as the evaporation source. A polyimide substrate is placed on a water-cooled copper heat sink to prevent it from being thermally damaged. With the aim of preventing oxidation of the deposited Cu film, we investigated the effect of adding H{sub 2} to Ar plasma on film characteristics. Theoretical fitting of the OH emission line in OES spectrum revealed that adding H{sub 2} gas significantly increased the rotational temperature roughly from 800 to 1500 K. The LMM Auger spectroscopy analysis revealed that higher-purity Cu films were synthesized on polyimide by adding hydrogen gas. A possible explanation for the enhancement in the Cu film deposition rate and improvement of purity of Cu films by H{sub 2} gas addition is that atomic hydrogen produced by the plasma plays important roles in heating the gas to promote the evaporation of Cu atoms from the Cu wire and removing oxygen from copper oxide components via reduction reaction.

Zhao, P. [Graduate School of Science and Technology, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8561 (Japan); Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031 (China); Zheng, W. [Research and Technology Center, Yazaki Corp., 1500 Misyuuku, Susono 410-1194 (Japan); Meng, Y. D. [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031 (China); Nagatsu, M. [Graduate School of Science and Technology, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8561 (Japan)

2013-03-28T23:59:59.000Z

206

Morphology and structure evolution of tin-doped indium oxide thin films deposited by radio-frequency magnetron sputtering: The role of the sputtering atmosphere  

SciTech Connect (OSTI)

The microstructure and morphology evolution of tin-doped indium oxide (ITO) thin films deposited by radio-frequency magnetron sputtering in different sputtering atmospheres were investigated by X-ray diffraction, X-ray reflectivity, and atomic force microscopy. The surface roughness w increases with increasing film thickness d{sub f}, and exhibits a power law behavior w???d{sub f}{sup ?}. The roughness decreases with increasing O{sub 2} flow, while it increases with increasing H{sub 2} flow. The growth exponent ? is found to be 0.35, 0.75, and 0.98 for depositions in Ar/10%O{sub 2}, pure Ar, and Ar/10%H{sub 2} atmospheres, respectively. The correlation length ? increases with film thickness also with a power law according to ????d{sub f}{sup z} with exponents z?=?0.36, 0.44, and 0.57 for these three different gas atmospheres, respectively. A combination of local and non-local growth modes in 2?+?1 dimensions is discussed for the ITO growth in this work.

Nie, Man, E-mail: man.nie@helmholtz-berlin.de; Mete, Tayfun; Ellmer, Klaus [Department of Solar Fuels and Energy Storage Materials, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D14109 Berlin (Germany)

2014-04-21T23:59:59.000Z

207

System Design for Cognitive Radio Communications  

E-Print Network [OSTI]

about an increasing demand for frequency spectrum. Cognitive radio offers a tempting solution, in which frequency bands that are not being used by their licensed users are utilized by cognitive radios. Since cognitive radios do not need to have a license and since they do not affect the operation

Arslan, HĂĽseyin

208

Radio frequency plasma power dependence of the moisture permeation barrier characteristics of Al{sub 2}O{sub 3} films deposited by remote plasma atomic layer deposition  

SciTech Connect (OSTI)

In the present study, we investigated the gas and moisture permeation barrier properties of Al{sub 2}O{sub 3} films deposited on polyethersulfone films (PES) by capacitively coupled plasma (CCP) type Remote Plasma Atomic Layer Deposition (RPALD) at Radio Frequency (RF) plasma powers ranging from 100 W to 400 W in 100 W increments using Trimethylaluminum [TMA, Al(CH{sub 3}){sub 3}] as the Al source and O{sub 2} plasma as the reactant. To study the gas and moisture permeation barrier properties of 100-nm-thick Al{sub 2}O{sub 3} at various plasma powers, the Water Vapor Transmission Rate (WVTR) was measured using an electrical Ca degradation test. WVTR decreased as plasma power increased with WVTR values for 400 W and 100 W of 2.6 × 10{sup ?4} gm{sup ?2}day{sup ?1} and 1.2 × 10{sup ?3} gm{sup ?2}day{sup ?1}, respectively. The trends for life time, Al-O and O-H bond, density, and stoichiometry were similar to that of WVTR with improvement associated with increasing plasma power. Further, among plasma power ranging from 100 W to 400 W, the highest power of 400 W resulted in the best moisture permeation barrier properties. This result was attributed to differences in volume and amount of ion and radical fluxes, to join the ALD process, generated by O{sub 2} plasma as the plasma power changed during ALD process, which was determined using a plasma diagnosis technique called the Floating Harmonic Method (FHM). Plasma diagnosis by FHM revealed an increase in ion flux with increasing plasma power. With respect to the ALD process, our results indicated that higher plasma power generated increased ion and radical flux compared with lower plasma power. Thus, a higher plasma power provides the best gas and moisture permeation barrier properties.

Jung, Hyunsoo [Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of) [Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Samsung Display Co. Ltd., Tangjeong, Chungcheongnam-Do 336-741 (Korea, Republic of); Choi, Hagyoung; Lee, Sanghun [Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of)] [Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Jeon, Heeyoung [Department of Nano-scale Semiconductor Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of)] [Department of Nano-scale Semiconductor Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Jeon, Hyeongtag [Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of) [Division of Materials Science and Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Department of Nano-scale Semiconductor Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of)

2013-11-07T23:59:59.000Z

209

Low reflectance radio frequency load  

DOE Patents [OSTI]

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

Ives, R. Lawrence; Mizuhara, Yosuke M

2014-04-01T23:59:59.000Z

210

Compact Low Frequency Radio Antenna  

DOE Patents [OSTI]

An antenna is disclosed that comprises a pair of conductive, orthogonal arches and a pair of conductive annular sector plates, wherein adjacent legs of each arch are fastened to one of the annular sector plates and the opposite adjacent pair of legs is fastened to the remaining annular sector plate. The entire antenna structure is spaced apart from a conductive ground plane by a thin dielectric medium. The antenna is driven by a feed conduit passing through the conductive ground plane and dielectric medium and attached to one of the annular sector plates, wherein the two orthogonal arched act as a pair of crossed dipole elements. This arrangement of elements provides a radiation pattern that is largely omni-directional above the horizon.

Punnoose, Ratish J. (Hayward, CA)

2008-11-11T23:59:59.000Z

211

Demonstration of Real-time Spectrum Sensing for Cognitive Radio  

E-Print Network [OSTI]

Demonstration of Real-time Spectrum Sensing for Cognitive Radio Zhe Chen, Nan Guo, and Robert C sensing detects the availability of the radio frequency spectrum in a real-time fashion, which is essen Cognitive radio (CR) has been put forward to make effi- cient use of scarce radio frequency spectrum

Qiu, Robert Caiming

212

Hybrid spread spectrum radio system  

DOE Patents [OSTI]

Systems and methods are described for hybrid spread spectrum radio systems. A method, includes receiving a hybrid spread spectrum signal including: fast frequency hopping demodulating and direct sequence demodulating a direct sequence spread spectrum signal, wherein multiple frequency hops occur within a single data-bit time and each bit is represented by chip transmissions at multiple frequencies.

Smith, Stephen F. (London, TN) [London, TN; Dress, William B. (Camas, WA) [Camas, WA

2010-02-09T23:59:59.000Z

213

E-Print Network 3.0 - adaptive radio resource Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Doctor Summary: schemes to optimally use the radio frequency and power resource in cognitive radio networks. The proposed... schemes will benefit not only network operators but...

214

Planck early results: Spectral energy distributions and radio continuum spectra of northern extragalactic radio sources  

E-Print Network [OSTI]

Spectral energy distributions (SEDs) and radio continuum spectra are presented for a northern sample of 104 extragalactic radio sources, based on the Planck Early Release Compact Source Catalog (ERCSC) and simultaneous multifrequency data. The nine Planck frequencies, from 30 to 857 GHz, are complemented by a set of simultaneous observations ranging from radio to gamma-rays. This is the first extensive frequency coverage in the radio and millimetre domains for an essentially complete sample of extragalactic radio sources, and it shows how the individual shocks, each in their own phase of development, moving in the relativistic jet, shape the radio spectra. The SEDs presented in this paper were fitted with second and third degree polynomials to estimate the frequencies of the synchrotron and inverse Compton (IC) peaks, and the spectral indices of low and high frequency radio data, including the Planck ERCSC data, were calculated. SED modelling methods are discussed, with an emphasis on proper, physical modelli...

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

2011-01-01T23:59:59.000Z

215

The number counts, luminosity functions and evolution of microwave-selected (WMAP) blazars and radio galaxies  

E-Print Network [OSTI]

(Abridged) We carried out an extensive search to identify the counterparts of all the sources listed in the WMAP 3-yr catalogue using literature and archival data. Our work led to the identification of 309 WMAP sources, 98% of which are blazars, radio quasars or radio galaxies. At present, 15 objects still remain without identification due to the lack of optical spectroscopic data or a clear radio counterpart. Our results allow us to define a flux limited sample of 203 high Galactic latitude microwave sources ($f_{41GHz} \\ge 1$ Jy, $|b_{\\rm II}| > 15^\\circ$) which is virtually completely identified (99%). The microwave band is ideally suited for blazar statistical studies since this is the part of the em spectrum that is least affected by the superposition of spectral components of different origin. Using this data-set we derived number counts, luminosity functions and cosmological evolution of blazars and radio galaxies at microwave frequencies. Our results are in good agreement with those found at radio fre...

Giommi, P; Padovani, P; Gasparrini, D; Cavazzuti, E; Cutini, S

2009-01-01T23:59:59.000Z

216

Unravelling lifecycles & physics of radio-loud AGN in the SKA era  

E-Print Network [OSTI]

Radio-loud AGN (>10^{22} W/Hz at 1.4 GHz) will be the dominant bright source population detected with the SKA. The high resolution that the SKA will provide even in wide-area surveys will mean that, for the first time sensitive, multi-frequency total intensity and polarisation imaging of large samples of radio-loud active galactic nuclei (AGN) will become available. The unprecedented sensitivity of the SKA coupled with its wide field of view capabilities will allow identification of objects of the same morphological type (i.e. the entire FR I, low- and high-luminosity FR II, disturbed morphology as well as weak radio-emitting AGN populations) up to high redshifts (z~4 and beyond), and at the same stage of their lives, from the youngest CSS/GPS sources to giant and fading (dying) sources, through to those with restarted activity radio galaxies and quasars. Critically, the wide frequency coverage of the SKA will permit analysis of same-epoch rest-frame radio properties, and the sensitivity and resolution will a...

Kapi?ska, Anna D; Jackson, Carole A; An, Tao; Baan, Willem A; Jarvis, Matt J

2014-01-01T23:59:59.000Z

217

The Radio Frequency Identification enabled logistics process for supply chain event management from China to the United States via Hong Kong  

E-Print Network [OSTI]

This thesis reviews the current logistics processes and issues for container shipments in the supply chain. In particular, the problems associated with container shipments from China to the US, via the Hong Kong Port, ...

Han, Taehee

2005-01-01T23:59:59.000Z

218

International Workshop on Radio Frequency Identification (RFID) and Wireless Sensors 11-13 November 2005, Indian Institute of Technology, Kanpur, India  

E-Print Network [OSTI]

Infrastructure B.S. Prabhu, Xiaoyong Su, Charlie Qiu, Harish Ramamurthy, Peter Chu, Rajit Gadh Wireless Internet

California at Los Angeles, University of

219

AUTO ID FUTURE - FREQUENCY AGNOSTIC  

E-Print Network [OSTI]

Identification of information is one key to the development of intelligent decision systems of the future. Frequency agnostic automatic identification is only one step in the physical world to make physical objects identify ...

DATTA, SHOUMEN

220

The radio spectrum of Sgr A*  

E-Print Network [OSTI]

We discuss the radio spectrum of Sgr A* \\index{Sgr A*, radio spectrum} in the frequency range between $\\approx 1\\,{\\rm GHz}$ and $\\approx 1\\,000\\,{\\rm GHz}$, show that it can be explained by optically thin synchrotron radiation \\index{Sgr A*, synchrotron radiation, optically thin} of relativistic electrons, and point toward a possible correlation between the spectrum of Sgr A* and larger-scale ($\\la 50\\,{\\rm pc}$) radio emission from the Galactic Center \\index{Galactic Center} region.

Wolfgang J. Duschl; Harald Lesch

1994-11-03T23:59:59.000Z

Note: This page contains sample records for the topic "radio frequency identification" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Hybrid spread spectrum radio system  

DOE Patents [OSTI]

Systems and methods are described for hybrid spread spectrum radio systems. A method includes modulating a signal by utilizing a subset of bits from a pseudo-random code generator to control an amplification circuit that provides a gain to the signal. Another method includes: modulating a signal by utilizing a subset of bits from a pseudo-random code generator to control a fast hopping frequency synthesizer; and fast frequency hopping the signal with the fast hopping frequency synthesizer, wherein multiple frequency hops occur within a single data-bit time.

Smith, Stephen F. (London, TN); Dress, William B. (Camas, WA)

2010-02-02T23:59:59.000Z

222

Cryptographic Link Signatures for Spectrum Usage Authentication in Cognitive Radio  

E-Print Network [OSTI]

Cryptographic Link Signatures for Spectrum Usage Authentication in Cognitive Radio Xi Tan, Kapil frequency spectrum was inefficiently utilized. To fully use these spectrums, cognitive radio networks have of cognitive radio is to enable the current fixed spectrum channels assigned by Federal Communica- tions

Du, Wenliang "Kevin"

223

Quickest Spectrum Detection Using Hidden Markov Model for Cognitive Radio  

E-Print Network [OSTI]

Quickest Spectrum Detection Using Hidden Markov Model for Cognitive Radio Zhe Chen, Zhen Hu, Robert and recognition under the umbrella of cognitive radio. In the procedure of spectrum recognition, a frequency) opened free white space spectrum on November 4, 2008 [1]. Cognitive radio has been put forward as a more

Qiu, Robert Caiming

224

KUAR: A Flexible Software-Defined Radio Development Platform  

E-Print Network [OSTI]

advanced research in the areas of wireless radio networks, dynamic spectrum access, and cognitive radios have shown that licensed spectrum is relatively unused across time and frequency [1, 2 Communications Magazine Feature Topic on Cognitive Radios for Dynamic Spectrum Access. Advanced Research Projects

Kansas, University of

225

MULTIMOMENT RADIO TRANSIENT DETECTION  

SciTech Connect (OSTI)

We present a multimoment technique for signal classification and apply it to the detection of fast radio transients in incoherently dedispersed data. Specifically, we define a spectral modulation index in terms of the fractional variation in intensity across a spectrum. A signal whose intensity is distributed evenly across the entire band has a lower modulation index than a spectrum whose intensity is localized in a single channel. We are interested in broadband pulses and use the modulation index to excise narrowband radio frequency interference by applying a modulation index threshold above which candidate events are removed. The technique is tested both with simulations and using data from known sources of radio pulses (RRAT J1928+15 and giant pulses from the Crab pulsar). The method is generalized to coherent dedispersion, image cubes, and astrophysical narrowband signals that are steady in time. We suggest that the modulation index, along with other statistics using higher order moments, should be incorporated into signal detection pipelines to characterize and classify signals.

Spitler, L. G.; Cordes, J. M.; Chatterjee, S. [Astronomy Department and NAIC, Cornell University, Ithaca, NY 14853 (United States); Stone, J., E-mail: lspitler@astro.cornell.edu [Department of Physics and Astronomy, Barnard College, New York, NY 10027 (United States)

2012-04-01T23:59:59.000Z

226

Spectrum Occupancy Analysis for Cognitive Radio Zhe Wang and Sana Salous  

E-Print Network [OSTI]

Spectrum Occupancy Analysis for Cognitive Radio Zhe Wang and Sana Salous School of Engineering frequency strategy has not been able to optimise the spectrum usage. Cognitive Radio could in theory allow spectrum to operate in. Cognitive Radio would hop into unused bands of the radio spectrum and hop out again

Haddadi, Hamed

227

Suppression of automotive radio frequency interference  

E-Print Network [OSTI]

'TBATIONS Pag~ 1. Thc Au tomo Li. ve Igni t ion Syst: em 2. Iquivalent Circuit for SLate Variable Analys. i. s 3. Osci. lloscope Presentation of Spar)c P) ug Gap Curron c 77ave form 15 4. k'atbcmat'c. , l Representation of Spark plug ' ap Current t7... ) ? dl. st. r& 0 t * (CD+1) ) & ond. ? d i s tr i. b uior corsducting n==7, 8, . . . 21 ))/?0 n=-7, . . . 2G spark plug not conducCing spar!c plug cor, ducting A suitable computer integration technique may be applied Lo these equati. ons to u...

McLaughlin, Cleon Crosby

1969-01-01T23:59:59.000Z

228

Light modulated switches and radio frequency emitters  

DOE Patents [OSTI]

The disclosure relates to a light modulated electron beam driven radiofrequency emitter. Pulses of light impinge on a photoemissive device which generates an electron beam having the pulse characteristics of the light. The electron beam is accelerated through a radiofrequency resonator which produces radiofrequency emission in accordance with the electron, hence, the light pulses.

Wilson, Mahlon T. (Los Alamos, NM); Tallerico, Paul J. (Los Alamos, NM)

1982-01-01T23:59:59.000Z

229

Dielectric supported radio-frequency cavities  

DOE Patents [OSTI]

A device which improves the electrical and thermomechanical performance of an RF cavity, for example, in a disk-loaded accelerating structure. A washer made of polycrystalline diamond is brazed in the middle to a copper disk washer and at the outer edge to the plane wave transformer tank wall, thus dissipating heat from the copper disk to the outer tank wall while at the same time providing strong mechanical support to the metal disk. The washer structure eliminates the longitudinal connecting rods and cooling channels used in the currently available cavities, and as a result minimizes problems such as shunt impedance degradation and field distortion in the plane wave transformer, and mechanical deflection and uneven cooling of the disk assembly.

Yu, David U. L. (Rancho Palos Verdes, CA); Lee, Terry G. (Cupertino, CA)

2000-01-01T23:59:59.000Z

230

Wide band stepped frequency ground penetrating radar  

DOE Patents [OSTI]

A wide band ground penetrating radar system (10) embodying a method wherein a series of radio frequency signals (60) is produced by a single radio frequency source (16) and provided to a transmit antenna (26) for transmission to a target (54) and reflection therefrom to a receive antenna (28). A phase modulator (18) modulates those portion of the radio frequency signals (62) to be transmitted and the reflected modulated signal (62) is combined in a mixer (34) with the original radio frequency signal (60) to produce a resultant signal (53) which is demodulated to produce a series of direct current voltage signals (66) the envelope of which forms a cosine wave shaped plot (68) which is processed by a Fast Fourier Transform unit 44 into frequency domain data (70) wherein the position of a preponderant frequency is indicative of distance to the target (54) and magnitude is indicative of the signature of the target (54).

Bashforth, Michael B. (Buellton, CA); Gardner, Duane (Santa Maria, CA); Patrick, Douglas (Santa Maria, CA); Lewallen, Tricia A. (Ventura, CA); Nammath, Sharyn R. (Santa Barbara, CA); Painter, Kelly D. (Goleta, CA); Vadnais, Kenneth G. (Alexandria, VA)

1996-01-01T23:59:59.000Z

231

Design of RF/IF analog to digital converters for software radio communication receivers  

E-Print Network [OSTI]

Software radio architecture can support multiple standards by performing analogto- digital (A/D) conversion of the radio frequency (RF) signals and running reconfigurable software programs on the backend digital signal processor (DSP). A slight...

Thandri, Bharath Kumar

2007-09-17T23:59:59.000Z

232

Emission altitude in radio pulsars  

E-Print Network [OSTI]

This paper presents a method of estimation of emission altitudes using observational data - precise measurements of pulse profile widths at low intensity level. The analysis of emission altitudes obtained using this method for a large number of pulsars gives constraints that should be useful for theory of coherent pulsar emission. It seems that radio emission originates at altitudes of about few percent of the light cylinder and that they depend on frequency, pulsar period and period derivative.

J. Kijak

2002-08-30T23:59:59.000Z

233

Correlation of pulsar radio emission spectrum with peculiarities of particle acceleration in a polar gap  

SciTech Connect (OSTI)

The analytical expression for the frequency of radio emission intensity maximum in pulsars with free electron emission from the stellar surface has been found. Peculiarities of the electron acceleration in a polar gap are considered. The correlation between the high-frequency cutoff and low-frequency turnover in the radio emission spectrum of pulsars known from observations has been explained.

Kontorovich, V. M., E-mail: vkont1001@yahoo.com; Flanchik, A. B. [National Academy of Sciences of Ukraine, Institute of Radio Astronomy (Ukraine)] [National Academy of Sciences of Ukraine, Institute of Radio Astronomy (Ukraine)

2013-01-15T23:59:59.000Z

234

Cognitive Radio Networks: How much Spectrum Sharing is Optimal?  

E-Print Network [OSTI]

Cognitive Radio Networks: How much Spectrum Sharing is Optimal? Sudhir Srinivasa and Syed Ali Jafar the traditional `divide and set aside' approach to spectrum regulation ensures that the licensed (primary) users periodically monitors the radio spectrum, intelligently detects occupancy in the different frequency bands

Jafar, Syed A.

235

> REPLACE THIS LINE WITH YOUR PAPER IDENTIFICATION NUMBER (DOUBLE-CLICK HERE TO EDIT) < 1 Abstract--In this letter, a novel linear frequency-domain  

E-Print Network [OSTI]

--In this letter, a novel linear frequency-domain compensation (FDC) of the resonant cavity light emitting diode emitting diodes (RC-LED) have been largely adopted in POF communications with on-off-keying modulation insensitivity, which are extremely suitable for optical home networking [2]. The low-cost resonant cavity light

Paris-Sud XI, Université de

236

Energy Efficient Radio Resource  

E-Print Network [OSTI]

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

Yanikomeroglu, Halim

237

Identification and Removal of High Frequency Temporal Noise in a Nd:YAG Macro-Pulse Laser Assisted with a Diagnostic Streak Camera  

SciTech Connect (OSTI)

This paper discusses the use of a reference streak camera (SC) to diagnose laser performance and guide modifications to remove high frequency noise from Bechtel Nevada's long-pulse laser. The upgraded laser exhibits less than 0.1% high frequency noise in cumulative spectra, exceeding National Ignition Facility (NIF) calibration specifications. Inertial Confinement Fusion (ICF) experiments require full characterization of streak cameras over a wide range of sweep speeds (10 ns to 480 ns). This paradigm of metrology poses stringent spectral requirements on the laser source for streak camera calibration. Recently, Bechtel Nevada worked with a laser vendor to develop a high performance, multi-wavelength Nd:YAG laser to meet NIF calibration requirements. For a typical NIF streak camera with a 4096 x 4096 pixel CCD, the flat field calibration at 30 ns requires a smooth laser spectrum over 33 MHz to 68 GHz. Streak cameras are the appropriate instrumentation for measuring laser amplitude noise at these very high frequencies since the upper end spectral content is beyond the frequency response of typical optoelectronic detectors for a single shot pulse. The SC was used to measure a similar laser at its second harmonic wavelength (532 nm), to establish baseline spectra for testing signal analysis algorithms. The SC was then used to measure the new custom calibration laser. In both spatial-temporal measurements and cumulative spectra, 6-8 GHz oscillations were identified. The oscillations were found to be caused by inter-surface reflections between amplifiers. Additional variations in the SC spectral data were found to result from temperature instabilities in the seeding laser. Based on these findings, laser upgrades were made to remove the high frequency noise from the laser output.

Kent Marlett, Bechtel Nevada; Ke-Xun Sun Bechtel Nevada

2004-09-23T23:59:59.000Z

238

Automatic calibration of modulated fractional-N frequency synthesizers  

E-Print Network [OSTI]

The focus of this research has been the development of a low power, radio frequency transmitter architecture. Specifically, a technique for in service automatic calibration of a modulated phase locked loop (PLL) frequency ...

McMahill, Dan

2001-01-01T23:59:59.000Z

239

CONTROL OF JOVIAN RADIO EMISSIONS BY THE GALILEAN MOONS AS OBSERVED BY  

E-Print Network [OSTI]

CONTROL OF JOVIAN RADIO EMISSIONS BY THE GALILEAN MOONS AS OBSERVED BY CASSINI AND GALILEO G. B can control a portion of the Jovian radio emission. More recent studies using the Galileo and Voyager­frequency Jovian decametric radio (DAM) emission. The Cassini gravity­assist flyby of Jupiter on December 30, 2000

Gurnett, Donald A.

240

Auction-based Agent Negotiation in Cognitive Radio Ad Hoc Networks  

E-Print Network [OSTI]

of spectrum. To solve the problem of congestion, cognitive radio networks use dynamic spectrum access spectrum access. 1 Introduction The Cognitive Radio (CR) is a form of wireless communication in which are not and can move to unused channels. This optimizes the use of available radio frequency spectrum while

Note: This page contains sample records for the topic "radio frequency identification" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

IEEE TRANSACTIONS ON SYSTEMS, MAN, AND CYBERNETICS PART B 1 Spectrum Sharing in Cognitive Radio Networks  

E-Print Network [OSTI]

IEEE TRANSACTIONS ON SYSTEMS, MAN, AND CYBERNETICS ­ PART B 1 Spectrum Sharing in Cognitive Radio of radio frequency spectrum. In this paper, we consider the problem of spectrum sharing among primary (or Terms--Cognitive radio, spectrum sensing, spectrum sharing, game theory, Nash equilibrium. I

Wang, Xinbing

242

Determination, Control & Improvement of an SKA Radio  

E-Print Network [OSTI]

SKA core sites were chosen in a sparsely populated part of South Africa, in the Northern Cape ProvinceDetermination, Control & Improvement of an SKA Radio Environment in South Africa Three potential -200 -150 -100 -50 0 Frequency spectrum 150 to 174 MHz Spectralpowerflux-density Agg Signal Kalahari

Ellingson, Steven W.

243

Preparing a public database of radio sources  

E-Print Network [OSTI]

We have collected the largest existing set of radio source lists in machine-readable form: 320 tables with 1.75 million records. Only a minor fraction of these is accessible via public databases. We describe our plans to make this huge amount of heterogeneous data accessible in a homogeneous way via the World Wide Web, with reliable cross-identifications, and searchable by various observables.

H. Andernach; S. A. Trushkin; A. G. Gubanov; O. V. Verkhodanov; V. B. Titov; A. Micol

1996-07-22T23:59:59.000Z

244

Radio flares from gamma-ray bursts  

E-Print Network [OSTI]

We present predictions of centimeter and millimeter radio emission from reverse shocks in the early afterglows of gamma-ray bursts with the goal of determining their detectability with current and future radio facilities. Using a range of GRB properties, such as peak optical brightness and time, isotropic equivalent gamma-ray energy and redshift, we simulate radio light curves in a framework generalized for any circumburst medium structure and including a parametrization of the shell thickness regime that is more realistic than the simple assumption of thick- or thin-shell approximations. Building on earlier work by Mundell et al. (2007) and Melandri et al. (2010) in which the typical frequency of the reverse shock was suggested to lie at radio, rather than optical wavelengths at early times, we show that the brightest and most distinct reverse-shock radio signatures are detectable up to 0.1 -- 1 day after the burst, emphasizing the need for rapid radio follow-up. Detection is easier for bursts with later opt...

Kopac, D; Kobayashi, S; Virgili, F J; Harrison, R; Japelj, J; Guidorzi, C; Melandri, A; Gomboc, A

2015-01-01T23:59:59.000Z

245

Radio Observations of High Redshift Radio Galaxies  

E-Print Network [OSTI]

We review some aspects of radio continuum polarimetric imaging of high redshift radio galaxies. The correlation between extreme values of Faraday rotation observed toward radio emitting structures in nearby radio galaxies, and X-ray emitting cluster atmospheres, is presented as a method for targeting objects at high redshift for deep X-ray searches. We present an X-ray detection of the extreme rotation measure radio galaxy PKS 1138-262 at z = 2.156, and we argue that the X-ray emission is from a cluster atmosphere with a luminosity of 1.7x10^{44} h^{-2} ergs sec^{-1}. We also present results on the correlation between size and redshift for a sample of ultra-luminous radio galaxies between 0 < z < 4.3. Source sizes decrease systematically with redshift, suggesting either denser environments, or younger sources, at high redshift. An alternative explanation is significant inverse Compton losses off the microwave background at high redshift.

C. L. Carilli; H. J. A. Rottgering; G. K. Miley L. Pentericci; D. E. Harris

1998-02-18T23:59:59.000Z

246

Optical and Near-IR Imaging of Ultra Steep Spectrum Radio Sources - The K-z diagram of radio and optically selected galaxies  

E-Print Network [OSTI]

We present optical and/or near-IR images of 128 ultra steep spectrum (USS) radio sources. Roughly half of the objects are identified in the optical images (R 94% are detected at K5). The major axes of the identifications in K-band are preferentially oriented along the radio axes, with half of them having compact morphologies. The 22 sources with spectroscopic redshifts and K-band magnitudes follow the K-z relation found from previous radio samples, but with a larger scatter. We argue that this may be due to a dependence of K-magnitude on the radio power, with the highest radio power sources inhabiting the most massive host galaxies. We present a composite K-z diagram of radio-loud and radio-quiet galaxies, selected from the HDF-North and the Hawaii surveys. Out to z radio-loud galaxies trace the bright envelope of the radio quiet galaxies, while at z >~ 1, the radio-loud galaxies are >~ 2 magnitudes brighter. We argue that this is not due to a contribution from the AGN or emission lines. This difference strongly suggests that radio galaxies pinpoint the most massive systems out to the highest known redshifts, probably due to the mutual correlation of the mass of the galaxy and the radio power on the mass of the central black hole.

Carlos De Breuck; Wil van Breugel; Adam Stanford; Huub Rottgering; George Miley; Daniel Stern

2001-09-28T23:59:59.000Z

247

Statistical identification  

E-Print Network [OSTI]

Statistical identification of critical, dependent and redundant articulators Veena D Singampalli of articulatory roles Evaluation by exhaustive search and trajectory generation Summary Statistical identification, Belgium #12;Statistical identification of critical, dependent and redundant articulators Veena D

Jackson, Philip JB

248

Statistical identification  

E-Print Network [OSTI]

Statistical identification of critical, dependent and redundant articulators Philip Jackson & Veena Statistical identification of critical, dependent and redundant articulators Philip Jackson & Veena Acoustics'08 Paris #12;Statistical identification of critical, dependent and redundant articulators Philip

Jackson, Philip JB

249

ON THE EVOLUTION OF THE CORES OF RADIO SOURCES AND THEIR EXTENDED RADIO EMISSION  

SciTech Connect (OSTI)

The work in this paper aims at determining the evolution and possible co-evolution of radio-loud active galactic nuclei (AGNs) and their cores via their radio luminosity functions (i.e., total and core RLFs, respectively). Using a large combined sample of 1063 radio-loud AGNs selected at low radio frequency, we investigate the RLF at 408 MHz of steep-spectrum radio sources. Our results support a luminosity-dependent evolution. Using core flux density data of the complete sample 3CRR, we investigate the core RLF at 5.0 GHz. Based on the combined sample with incomplete core flux data, we also estimate the core RLF using a modified factor of completeness. Both results are consistent and show that the comoving number density of radio cores displays a persistent decline with redshift, implying a negative density evolution. We find that the core RLF is obviously different from the total RLF at the 408 MHz band which is mainly contributed by extended lobes, implying that the cores and extended lobes could not be co-evolving at radio emission.

Yuan Zunli; Wang Jiancheng, E-mail: yuanzunli@ynao.ac.cn [National Astronomical Observatories, Yunnan Observatory, Chinese Academy of Sciences, Kunming 650011 (China)

2012-01-10T23:59:59.000Z

250

NATIONAL RADIO ASTRONOMY OBSERVATORY Green Bank, West Virginia  

E-Print Network [OSTI]

NATIONAL RADIO ASTRONOMY OBSERVATORY Green Bank, West Virginia Electronics Division Internal Report No. 109 BATTERY PACK FOR HEWLETT-PACKARD 5065A RUBIDIUM FREQUENCY STANDARD Michael Balister OCTOBER 1971 NUMBER OF COPIES: 150 #12;BATTERY PACK FOR HEWLETT-PACKARD 5065A RUBIDIUM FREQUENCY STANDARD

Groppi, Christopher

251

Modelling radio communication  

E-Print Network [OSTI]

realistic models of application layer #12;Example ­ multiple radios #12;Very common scenario · HTTP GETModelling radio communication from the perspective of mobile apps Jukka Suomela · Aalto University · Finland WRAWN · 15 July 2014 Addressing real-world challenges, building on existing infrastructure #12

Suomela, Jukka

252

Smart Radio Spectrum Management for Cognitive Radio  

E-Print Network [OSTI]

Today's wireless networks are characterized by fixed spectrum assignment policy. The limited available spectrum and the inefficiency in the spectrum usage necessitate a new communication paradigm to exploit the existing wireless spectrum opportunistically. Cognitive radio is a paradigm for wireless communication in which either a network or a wireless node changes its transmission or reception parameters to communicate efficiently avoiding interference with licensed or unlicensed users. In this work, a fuzzy logic based system for spectrum management is proposed where the radio can share unused spectrum depending on some parameters like distance, signal strength, node velocity and availability of unused spectrum. The system is simulated and is found to give satisfactory results.

Bhattacharya, Partha Pratim; Gera, Rishita; Agarwal, Anjali

2011-01-01T23:59:59.000Z

253

Cognitive Radio will revolutionize American transportation  

ScienceCinema (OSTI)

Cognitive Radio will revolutionize American transportation. Through smart technology, it will anticipate user needs; detect available bandwidths and frequencies then seamlessly connect vehicles, infrastructures, and consumer devices; and it will support the Department of Transportation IntelliDrive Program, helping researchers, auto manufacturers, and Federal and State officials advance the connectivity of US transportation systems for improved safety, mobility, and environmental conditions. Using cognitive radio, a commercial vehicle will know its driver, onboard freight and destination route. Drivers will save time and resources communicating with automatic toll booths and know ahead of time whether to stop at a weigh station or keep rolling. At accident scenes, cognitive radio sensors on freight and transportation modes can alert emergency personnel and measure on-site, real-time conditions such as a chemical leak. The sensors will connect freight to industry, relaying shipment conditions and new delivery schedules. For industry or military purposes, cognitive radio will enable real-time freight tracking around the globe and its sensory technology can help prevent cargo theft or tampering by alerting shipper and receiver if freight is tampered with while en route. For the average consumer, a vehicle will tailor the transportation experience to the passenger such as delivering age-appropriate movies via satellite. Cognitive radio will enhance transportation safety by continually sensing what is important to the user adapting to its environment and incoming information, and proposing solutions that improve mobility and quality of life.

None

2013-12-06T23:59:59.000Z

254

Cognitive Radio will revolutionize American transportation  

SciTech Connect (OSTI)

Cognitive Radio will revolutionize American transportation. Through smart technology, it will anticipate user needs; detect available bandwidths and frequencies then seamlessly connect vehicles, infrastructures, and consumer devices; and it will support the Department of Transportation IntelliDrive Program, helping researchers, auto manufacturers, and Federal and State officials advance the connectivity of US transportation systems for improved safety, mobility, and environmental conditions. Using cognitive radio, a commercial vehicle will know its driver, onboard freight and destination route. Drivers will save time and resources communicating with automatic toll booths and know ahead of time whether to stop at a weigh station or keep rolling. At accident scenes, cognitive radio sensors on freight and transportation modes can alert emergency personnel and measure on-site, real-time conditions such as a chemical leak. The sensors will connect freight to industry, relaying shipment conditions and new delivery schedules. For industry or military purposes, cognitive radio will enable real-time freight tracking around the globe and its sensory technology can help prevent cargo theft or tampering by alerting shipper and receiver if freight is tampered with while en route. For the average consumer, a vehicle will tailor the transportation experience to the passenger such as delivering age-appropriate movies via satellite. Cognitive radio will enhance transportation safety by continually sensing what is important to the user adapting to its environment and incoming information, and proposing solutions that improve mobility and quality of life.

None

2013-07-22T23:59:59.000Z

255

Giant Radio Pulses from the Millisecond Pulsar PSR B1937+21 at 327 MHz  

E-Print Network [OSTI]

Seven giant radio pulses were recorded from the millisecond pulsar PSR B1937+21 during $\\approx$ 8.1 minutes observation by the Ooty Radio Telescope (ORT) at 326.5 MHz. Although sparse, these observations support most of the giant pulse behavior reported at higher radio frequencies (430 to 2380 MHz). Within the main componentof the integrated profile, they are emitted only in a narrow ($\\la$ 47 $\\mu$s) window of pulse phase, close to its peak. This has important implications for doing super-high precision timing of PSR B1937+21 at low radio frequencies.

M. Vivekanand

2002-05-13T23:59:59.000Z

256

MEASURING THE JET POWER OF FLAT-SPECTRUM RADIO QUASARS  

SciTech Connect (OSTI)

We use frequency-dependent position shifts of flat-spectrum radio cores to estimate the kinetic power of active galactic nucleus (AGN) jets. We find a correlation between the derived jet powers and AGN narrow-line luminosity, consistent with the well-known relation for radio galaxies and steep spectrum quasars. This technique can be applied to intrinsically weak jets even at high redshift.

Shabala, S. S.; Santoso, J. S. [School of Mathematics and Physics, University of Tasmania, Private Bag 37, Hobart, TAS 7001 (Australia); Godfrey, L. E. H. [International Centre for Radio Astronomy Research, Curtin University, GPO Box U1987, Perth, Western Australia 6845 (Australia)

2012-09-10T23:59:59.000Z

257

ON THE EXISTENCE OF 'RADIO THERMALLY ACTIVE' GALACTIC SUPERNOVA REMNANTS  

SciTech Connect (OSTI)

In this paper, we investigate the possibility of significant production of thermal bremsstrahlung radiation at radio continuum frequencies that could be linked to some Galactic supernova remnants (SNRs). The main targets for this investigation are SNRs expanding in high-density environments. There are several indicators of radio thermal bremsstrahlung radiation from SNRs, such as a flattening at higher frequencies and thermal absorption at lower frequencies intrinsic to an SNR. In this work, we discuss the radio continuum properties of three SNRs that are the best candidates for testing our hypothesis of significant thermal emission. In the case of SNRs IC 443 and 3C 391, thermal absorption has been previously detected. For IC 443, the contribution of thermal emission at 1 GHz, from our model fit is 3%-57%. It is similar to the estimate obtained from the thermal absorption properties (10%-40% at 1 GHz). In the case of the 3C 391 the conclusions are not so clear. The results from our model fit (thermal emission contribution of 10%-25% at 1 GHz) and results obtained from the low-frequency absorption (thermal contribution of 0.15%-7% at 1 GHz) do not overlap. For the SNR 3C 396 we suggest that if previously detected thermal absorption could be intrinsic to the SNR then the thermal emission (<47% at 1 GHz from our model fit) could be significant enough to shape the radio continuum spectrum at high frequencies. Polarization observations for these SNRs can constrain the strength of a thermal component. Reliable observations at low frequencies (<100 MHz) are needed as well as more data at high radio frequencies (>1 GHz), in order to make stronger conclusions about the existence of 'radio thermally active' SNRs.

Onic, D.; Urosevic, D.; Arbutina, B. [Department of Astronomy, Faculty of Mathematics, University of Belgrade (Serbia); Leahy, D. [Department of Physics and Astronomy, University of Calgary (Canada)

2012-09-01T23:59:59.000Z

259

The Impact of Frequency-Agility on Dynamic Spectrum Sharing  

E-Print Network [OSTI]

The Impact of Frequency-Agility on Dynamic Spectrum Sharing Lili Cao, Lei Yang and Haitao Zheng}@cs.ucsb.edu Abstract-- Designed to adapt spectrum usage on-the-fly, frequency-agile radios can drastically improve complexity. This motivates us to understand when and why having higher degree of frequency-agility helps

Almeroth, Kevin C.

260

Radio and Spectrum Management | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

Radio and Spectrum Management Radio and Spectrum Management DOE Radio and Spectrum Workshop 43.pdf More Documents & Publications ICAM Workshop Ad Hoc Meetings Spectrum Technology...

Note: This page contains sample records for the topic "radio frequency identification" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Cognitive Radio Networks as Sensor Networks  

E-Print Network [OSTI]

is used, assuming the cognitive radios know their ownfor Embedded Networked Sensing Cognitive Radio Networks AsJ. Pottie Introduction: Cognitive Radio (CR) Networks The

Bandari, Dorna; Yang, Seung R.; Zhao, Yue; Pottie, Gregory

2007-01-01T23:59:59.000Z

262

Radar network communication through sensing of frequency hopping  

DOE Patents [OSTI]

In one embodiment, a radar communication system includes a plurality of radars having a communication range and being capable of operating at a sensing frequency and a reporting frequency, wherein the reporting frequency is different than the sensing frequency, each radar is adapted for operating at the sensing frequency until an event is detected, each radar in the plurality of radars has an identification/location frequency for reporting information different from the sensing frequency, a first radar of the radars which senses the event sends a reporting frequency corresponding to its identification/location frequency when the event is detected, and all other radars in the plurality of radars switch their reporting frequencies to match the reporting frequency of the first radar upon detecting the reporting frequency switch of a radar within the communication range. In another embodiment, a method is presented for communicating information in a radar system.

Dowla, Farid; Nekoogar, Faranak

2013-05-28T23:59:59.000Z

263

Z mode waves as the source of Saturn narrowband radio emissions  

E-Print Network [OSTI]

Z mode waves as the source of Saturn narrowband radio emissions ShengYi Ye,1 J. D. Menietti,1 G emissions observed by the Cassini Radio and Plasma Waves Science (RPWS) instrument during high latitude perikrone passes. The narrowband emissions observed below the local electron cyclotron frequency ( fce

Gurnett, Donald A.

264

Green radio despite "Dirty RF" front-end Myriam Ariaudo*1  

E-Print Network [OSTI]

Green radio despite "Dirty RF" front-end Myriam Ariaudo*1 , Inbar Fijalkow1 , Jean-Luc Gautier1 in order to contribute in a Green radio development. In fact, the effects of typical RF imperfections, like algorithms are applied. Such algorithms enable Green applications (e.g., Orthogonal Frequency Division

Fijalkow, Inbar

265

Fast Neighbor Discovery with Lightweight Termination Detection in Heterogeneous Cognitive Radio Networks  

E-Print Network [OSTI]

the congestion within the frequency spectrum. A cognitive radio transceiver can operate over a wide range of the spectrum that the CR node can operate on may be allocated to licensed users who are known as primary usersFast Neighbor Discovery with Lightweight Termination Detection in Heterogeneous Cognitive Radio

Mittal, Neeraj

266

Effects of Bit Allocation on Non-contiguous Multicarrier-based Cognitive Radio Transceivers  

E-Print Network [OSTI]

of the licensed spectrum is relatively un- used across time and frequency [1]. Nevertheless, current regu- latory flexibility and access to spectrum. To exploit the advantages of cognitive radio transceivers and enableEffects of Bit Allocation on Non-contiguous Multicarrier-based Cognitive Radio Transceivers

Kansas, University of

267

Graph-based Criteria for Spectrum-Aware Clustering in Cognitive Radio Milan Bradonjica, Loukas Lazosb,  

E-Print Network [OSTI]

Graph-based Criteria for Spectrum-Aware Clustering in Cognitive Radio Networks Milan Bradonji, Arizona Email: llazos@ece.arizona.edu Abstract Cognitive radios (CRs) can exploit vacancies in licensed. 1. Introduction Under a fixed spectrum allocation paradigm, frequency bands are licensed

Lazos, Loukas

268

Uplink Cell Capacity of Cognitive Radio Networks with Peak Interference Power Constraints  

E-Print Network [OSTI]

.wang@hw.ac.uk.john.thompson@ed.ac.uk Abstract-A cognitive radio (secondary) network can reuse the under-utilized spectrum licensed to a primary. I. INTRODUCTION The radio spectrum is a precious natural resource that underpins various wireless frequency bands to license holders for exclusive use. Such a static spectrum licensing policy eliminates

Wang, Cheng-Xiang

269

Deep ATLAS radio observations of the CDFS-SWIRE field  

E-Print Network [OSTI]

We present the first results from the Australia Telescope Large Area Survey (ATLAS), which consist of deep radio observations of a 3.7 square degree field surrounding the Chandra Deep Field South, largely coincident with the infrared Spitzer Wide-Area Extragalactic (SWIRE) Survey. We also list cross-identifications to infrared and optical photometry data from SWIRE, and ground-based optical spectroscopy. A total of 784 radio components are identified, corresponding to 726 distinct radio sources, nearly all of which are identified with SWIRE sources. Of the radio sources with measured redshifts, most lie in the redshift range 0.5-2, and include both star-forming galaxies and active galactic nuclei (AGN). We identify a rare population of infrared-faint radio sources which are bright at radio wavelengths but are not seen in the available optical, infrared, or X-ray data. Such rare classes of sources can only be discovered in wide, deep surveys such as this.

Ray P. Norris; Jose Afonso; Phil N. Appleton; Brian J. Boyle; Paolo Ciliegi; Scott M. Croom; Minh T. Huynh; Carole A. Jackson; Anton M. Koekemoer; Carol J. Lonsdale; Enno Middelberg; Bahram Mobasher; Seb J. Oliver; Mari Polletta; Brian D. Siana; Ian Smail; Maxim A. Voronkov

2006-10-18T23:59:59.000Z

270

Spectrum Management for Cognitive Radio based on Genetics Algorithm  

E-Print Network [OSTI]

Spectrum scarceness is one of the major challenges that the present world is facing. The efficient use of existing licensed spectrum is becoming most critical as growing demand of the radio spectrum. Different researches show that the use of licensed are not utilized inefficiently. It has been also shown that primary user does not use more than 70% of the licensed frequency band most of the time. Many researchers are trying to found the techniques that efficiently utilize the under-utilized licensed spectrum. One of the approaches is the use of "Cognitive Radio". This allows the radio to learn from its environment, changing certain parameters. Based on this knowledge the radio can dynamically exploit the spectrum holes in the licensed band of the spectrum. This paper w i l l focus on the performance of spectrum allocation technique, based on popular meta-heuristics Genetics Algorithm and analyzing the performance of this technique using Mat Lab.

Singh, Santosh Kumar; Pathak, Vibhakar; Roy, Dr Krishna Chandra

2011-01-01T23:59:59.000Z

271

First `Winged' and `X'-shaped Radio Source Candidates  

SciTech Connect (OSTI)

A small number of double-lobed radio galaxies (17 from our own census of the literature) show an additional pair of low surface brightness ''wings'', thus forming an overall ''X''-shaped appearance. The origin of the wings in these radio sources is unclear. They may be the result of back-flowing plasma from the currently active radio lobes into an asymmetric medium surrounding the active nucleus, which would make these ideal systems in which to study thermal/non-thermal plasma interactions in extragalactic radio sources. Another possibility is that the wings are the aging radio lobes left over after a (rapid) realignment of the central supermassive black-hole/accretion disk system due perhaps to a merger. Generally, these models are not well tested; with the small number of known examples, previous works focused on detailed case studies of selected sources with little attempt at a systematic study of a large sample. Using the VLA-FIRST survey database, we are compiling a large sample of winged and X-shaped radio sources for such studies. As a first step toward this goal, an initial sample of 100 new candidate objects of this type are presented in this paper. The search process is described, optical identifications from available literature data, and basic radio data are presented. From the limited resolution FIRST images ({approx} 5''), we can already confidently classify a sufficient number of these objects as having the characteristic wing lengths >80% of the active lobes to more than double the number of known X-shaped radio sources. We have also included as candidates, radio sources with shorter wings (<80% wing to lobe length ratios), or simply ''winged'' sources, as it is probable that projection effects are important. Finally, among the candidates are four quasars (z=0.37 to 0.84), and several have morphologies suggestive of Fanaroff-Riley type-I (low-power) radio galaxies. While followup observations are necessary to confirm these identifications, this stresses the importance of source orientation and imaging limitations in finding these enigmatic objects.

Cheung, C.C.

2007-01-22T23:59:59.000Z

272

Cognitive Radio: Fundamentals and Opportunities  

E-Print Network [OSTI]

Cognitive Radio: Fundamentals and Opportunities Robert H. Morelos-Zaragoza Department of Electrical Engineering San Jose State University October 12, 2007 #12;Cognitive Radio - RHMZ - 2007 Slide 2 of 18 Outline. Cognitive radio (CR) a) Definition and overview (Mitola) b) CR features (FCC) 3. Unlicensed TV spectrum

Morelos-Zaragoza, Robert H.

273

Game Theoretic Issues in Cognitive Radio Systems (Invited Paper)  

E-Print Network [OSTI]

licensed spectrum bands are under-utilized. This fact motivates the development of new technologies is to split the available spectrum into frequency bands and allocate them to different licensed (primary) users, the dynamic spectrum access in cognitive radio systems improves the spectrum utilization

Krishnamurthy, Vikram

274

The Throughput Potential of Cognitive Radio: A Theoretical Perspective  

E-Print Network [OSTI]

solutions to the problem of overcrowded and inefficient licensed spectrum. In this work we explore. This kind of spectrum licensing has created a very crowded spectrum as the FCC's frequency allocation chart of the spectrum. In a very broad sense, the term `cognitive radio' can be used to refer to various solutions

Jafar, Syed A.

275

RASDR: Benchtop Demonstration of SDR for Radio Astronomy  

SciTech Connect (OSTI)

The Society of Amateur Radio Astronomers (SARA) members present the benchtop version of RASDR, a Software Defined Radio (SDR) that is optimized for Radio Astronomy. RASDR has the potential to be a common digital receiver interface useful to many SARA members. This document describes the RASDR 0.0 , which provides digitized radio data to a backend computer through a USB 2.0 interface. A primary component of RASDR is the Lime Microsystems Femtocell chip which tunes from a 0.4-4 GHz center frequency with several selectable bandwidths from 0.75 MHz to 14 MHz. A second component is a board with a Complex Programmable Logic Device (CPLD) chip that connects to the Femtocell and provides two USB connections to the backend computer. A third component is an analog balanced mixer up conversion section. Together these three components enable RASDR to tune from 0.015 MHz thru 3.8GHz of the radio frequency (RF) spectrum. We will demonstrate and discuss capabilities of the breadboard system and SARA members will be able to operate the unit hands-on throughout the workshop.

Vacaliuc, Bogdan [ORNL] [ORNL; Oxley, Paul [Retired] [Retired; Fields, David [ORNL] [ORNL; Kurtz, Dr. Stan [Universidad Nacional Autonoma de Mexico (UNAM)] [Universidad Nacional Autonoma de Mexico (UNAM); Leech, Marcus [Shirleys Bay Radio Astronomy Consortium] [Shirleys Bay Radio Astronomy Consortium

2012-01-01T23:59:59.000Z

276

K-BAND RADIO FREQUENCY INTERFERENCE SURVEY OF SOUTHEASTERN MICHIGAN  

E-Print Network [OSTI]

antenna followed by the calibration switch, which alternates from the antenna to the warm load or the cold an overview of the RISE radiometer hardware, followed by a description of the execution of the RISE flight campaign in Section III. A discussion of the RISE measurements and analysis will follow in Section IV

Ruf, Christopher

277

Advanced Radio Frequency-Based Sensors for Monitoring Diesel...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Directions in Engine-Efficiency and Emissions Research (DEER) Conference in Detroit, MI, September 27-30, 2010. deer10sappok.pdf More Documents & Publications Development of...

278

Radio frequency wave experiments on the MST reversed field pinch  

SciTech Connect (OSTI)

Experiments, simulations, and theory all indicate that the magnetic fluctuations responsible for the poor confinement in the reversed field pinch (RFP) can be controlled by altering the radial profile of the current density. The magnetic fluctuations in the RFP are due to resistive MHD instabilities caused by current profile peaking; thus confinement in the RFP is ultimately the result of a misalignment between inductively driven current profiles and the stable current profiles characteristic of the Taylor state. If a technique such as rf current drive can be developed to non-inductively sustain a Taylor state (a current profile linearly stable to all tearing modes), the confinement of the RFP and its potential as a reactor concept are likely to increase. Whether there is a self-consistent path from poor confinement to greatly improved confinement through current profile modification is an issue for future experiments to address if and only if near term experiments can demonstrate: (1) coupling to and the propagation of rf waves in RFP plasmas, (2) efficient current drive, and (3) control of the power deposition which will make it possible to control the current profile. In this paper, modeling results and experimental plans are presented for two rf experiments which have the potential of satisfying these three goals: high-n{sub {parallel}} lower hybrid (LH) waves and electron Bernstein waves (EBWs).

Forest, C.B.; Chattopadhyay, P.K.; Nornberg, M.D.; Prager, S.C.; Thomas, M.A. [Univ. of Wisconsin, Madison, WI (United States). Physics Dept.; Uchimoto, E. [Univ. of Montana, Missoula, MT (United States). Dept. of Physics and Astronomy; Smirnov, A.P. [Moscow State Univ. (Russian Federation); Harvey, R.W. [CompX, Del Mar, CA (United States); Ram, A.K. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Plasma Fusion Center

1999-04-01T23:59:59.000Z

279

Tabu Search for Frequency Assignment in Mobile Radio Networks \\Lambda  

E-Print Network [OSTI]

in a regular spiral pattern to minimize the electromagnetic interference between adjacent pairs · Often used foil or braid to insulate the pair from electromagnetic interference · UTP (unshielded twisted pair

Hao, Jin-Kao

280

Towards Optimization of Probe Placement for Radio-Frequency Ablation  

E-Print Network [OSTI]

's electric potential and of the steady state of the heat distribution during RF ablation. The optimization with mono- or bipolar systems: A probe, connected to an electric generator, is placed inside the malignant tissue, such that an electric current flows through the body and heats the tissue near the probe up

Preusser, Tobias

Note: This page contains sample records for the topic "radio frequency identification" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Radio-frequency quadrupole resonator for linear accelerator  

DOE Patents [OSTI]

An RFQ resonator for a linear accelerator having a reduced level of interfering modes and producing a quadrupole mode for focusing, bunching and accelerating beams of heavy charged particles, with the construction being characterized by four elongated resonating rods within a cylinder with the rods being alternately shorted and open electrically to the shell at common ends of the rods to provide an LC parallel resonant circuit when activated by a magnetic field transverse to the longitudinal axis.

Moretti, A.

1982-10-19T23:59:59.000Z

282

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

SciTech Connect (OSTI)

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#11;-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.

Ruzic, David N. [University of Illinois at Urbana-Champaign, IL (United States)

2013-04-29T23:59:59.000Z

283

FAILURE DATA ANALYSIS OF THE SUPERHILAC RADIO FREQUENCY SUBSYSTEM  

E-Print Network [OSTI]

Operations Research Center (ORC) for their assistance andto Eduardo Ruiz-Esparza o' ORC for his excellent programmingthe SuperHILAC Accelerator," ORC 77-11, Operations Research

Chang, Mark K.

2012-01-01T23:59:59.000Z

284

Radio Frequency Diesel Particulate Filter Sensor Reduces Fuel...  

Office of Environmental Management (EM)

this process, known as regeneration, to only occur when needed, thereby reducing fuel consumption and enabling longer filter life. The RF-DPF can be used with light- and...

285

RFQ (radio-frequency quadrupole) accelerator tuning system  

DOE Patents [OSTI]

A cooling system is provided for maintaining a preselected operating temperature in a device, which may be an RFQ accelerator, having a variable heat removal requirement, by circulating a cooling fluid through a cooling system remote from the device. Internal sensors in the device enable an estimated error signal to be generated from parameters which are indicative of the heat removal requirement from the device. Sensors are provided at predetermined locations in the cooling system for outputting operational temperature signals. Analog and digital computers define a control signal functionally related to the temperature signals and the estimated error signal, where the control signal is defined effective to return the device to the preselected operating temperature in a stable manner. The cooling system includes a first heat sink responsive to a first portion of the control signal to remove heat from a major portion of the circulating fluid. A second heat sink is responsive to a second portion of the control to remove heat from a minor portion of the circulating fluid. The cooled major and minor portions of the circulating fluid are mixed in responsive to a mixing portion of the control signal, which is effective to proportion the major and minor portions of the circulating fluid to establish a mixed fluid temperature which is effective to define the preselected operating temperature for the remote device. 3 figs., 2 tabs.

Bolie, V.W.

1988-04-12T23:59:59.000Z

286

The modification of a radio frequency Cockcroft Walton generator  

E-Print Network [OSTI]

I A" , I' voC. VnPVVI O . I Figure 5. Schematio of 300 kc supply 500 ke P0~:i. ih SUPPLY COf'3 QN. NTS Nl 50000 eha, 10??aet R2 15%% oha? 10??att R3 ?50000 eha? 2C0??att &000 oha? 20 ~tt Cl? C2? C)? Cg ?01 ufd? 600 volt . "'iea C5 - 100 m...? 1000 volt Nice C6 - 600 guf? 600 volt Rica Cp &00 uaf? Reeelvinf Type Variable Cg? C9? 11650 uuf? 600 volte 10? Cll? 200 uufd? Trane aittinf, Type Variable? Split etaeor C12 +M4 ufd? 12500 volte C13? Cl~? ?1 ufd, 1000 volte C15 - National Type...

Holt, Joseph Marion

1954-01-01T23:59:59.000Z

287

Radio frequency circuits for wireless receiver front-ends  

E-Print Network [OSTI]

The beginning of the 21st century sees great development and demands on wireless communication technologies. Wireless technologies, either based on a cable replacement or on a networked environment, penetrate our daily life more rapidly than ever...

Xin, Chunyu

2005-11-01T23:59:59.000Z

288

Switchable and Tunable Ferroelectric Thin Film Radio Frequency  

E-Print Network [OSTI]

Beach, Terre Briggs, Timothy Brock, Russ Clifford, Phil Collica, Ning Gulari, Robert Hower, James Kulman

Sarabandi, Kamal

289

Narrowband high temperature superconducting receiver for low frequency radio waves  

DOE Patents [OSTI]

An underground communicating device has a low-noise SQUID using high temperature superconductor components connected to detect a modulated external magnetic flux for outputting a voltage signal spectrum that is related to the varying magnetic flux. A narrow bandwidth filter may be used to select a portion of the voltage signal spectrum that is relatively free of power line noise to output a relatively low noise output signal when operating in a portion of the electromagnetic spectra where such power line noise exists. A demodulator outputs a communication signal, which may be an FM signal, indicative of a modulation on the modulated external magnetic flux.

Reagor, David W. (Los Alamos, NM)

2001-01-01T23:59:59.000Z

290

Radio Frequency Diesel Particulate Filter Sensor Reduces Fuel Consumption,  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE: AlternativeEnvironment,Institutes and Launches theResidential Buildings » ZeroWins R&D 100

291

Advanced Radio Frequency-Based Sensors for Monitoring Diesel Particulate  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-Up fromDepartment of EnergyAdministrative2| Department of Energy 2

292

Radio Frequency Engineering, MDE, Accelerator Operations and Technology,  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security Administration the1 -the Mid-Infrared at 278, 298, and 323Program Accomplishments of themeeting,AOT:

293

Method and Apparatus for Pasteurizing Shell Eggs Using Radio Frequency  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment Surfaces andMapping theEnergy StorageAdvancedMetamaterials Researchsc-Storage

294

Microwave (MW) and Radio Frequency (RF) as Enabling Technologies for  

Broader source: Energy.gov (indexed) [DOE]

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May Jun Jul(Summary) "ofEarly Careerlumens_placard-green.eps MoreWSRC-STI-2007-00250 Rev. 05 Oak09 U . SThe March 23,Advanced

295

Microwave and Radio Frequency Workshop | Department of Energy  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:Year in3.pdfEnergy HealthComments MEMA:May1.docEx5.doc MicrosoftSJ-RT Smith Jones Rapid

296

Radio Frequency & Microwave Energy for the Petro Chemical Industry  

E-Print Network [OSTI]

Electro-Magnetic Energy has finally made its way into the Petro-Chemical market twenty-five years after market acceptance in the Food Processing Industry. Major factors influencing this change are tighter environmental regulations, price competition...

Raburn, R.

297

Radio Astronomy Fundamentals I John Simonetti  

E-Print Network [OSTI]

Radio Astronomy Fundamentals I John Simonetti Spring 2012 Radio astronomy provides a very different view of the universe than optical astronomy. Radio astronomers and optical astronomers use astronomy. Radio astronomers talk about sources of radio emission. Cas A is a strong source, for example

Ellingson, Steven W.

298

2010 Raj JainCSE574sWashington University in St. Louis Radio FrequencyRadio Frequency  

E-Print Network [OSTI]

, Magnetic Ink Character Recognition (MICR) on Bank Checks #12;24-4 ©2010 Raj JainCSE574s: Powered by incoming RF. Smaller, cheaper, long-life. Approx range 5m. Active Tags: Battery powered. Can power. Battery for logic. Range like passive. Reliability like active. #12;24-8 ©2010 Raj JainCSE574s

Jain, Raj

299

2006 Raj JainCSE574sWashington University in St. Louis Radio FrequencyRadio Frequency  

E-Print Network [OSTI]

, Magnetic Ink Character Recognition (MICR) on Bank Checks #12;18-4 ©2006 Raj JainCSE574s by incoming RF. Smaller, cheaper, long-life. Approx range 5m. " Active Tags: Battery powered. Can be read 100 power. Battery for logic. Range like passive. Reliability like active. #12;18-7 ©2006 Raj JainCSE574s

Jain, Raj

300

The jet-disk symbiosis. I. Radio to X-ray emission models for quasars  

E-Print Network [OSTI]

Starting from the assumption that radio jets and accretion disks are symbiotic features present in radio loud and radio quiet quasars we scale the bulk power of radio jets with the accretion power by adding mass- and energy conservation of the whole jet-disk system to the standard Blandford \\& K\\"onigl theory for compact radio cores. The model depends on only few parameters and can be constrained by observations. Thus we are able to show that radio and X-ray fluxes (SSC emission) of cores and lobes and typical dimensions of radio loud quasars are consistent with a jet being produced in the central engine. We present a synthetic broadband spectrum from radio to X-ray for a jet-disk system. The only way to explain the high efficiency of radio loud objects is to postulate that these objects consist of `maximal jets' with `total equipartition' where the magnetic energy flow of the jet is comparable to the kinetic jet power and the total jet power is a large fraction of the disk power. As the number of electrons is limited by the accretion flow, this is only possible when the minimum Lorentz factor of the electron distribution is $\\gamma_{\\rm e,min}\\ga100$ ($E\\ga 50 {\\rm MeV}$) or/and a large number of pairs are present. Such an electron/positron population would be a necessary consequence of hadronic interactions and may lead to some interesting effects in the low frequency self-absorbed spectrum. Emission from radio weak quasars can be explained with an initially identical jet. The difference between radio loud and radio weak could be due to a different efficiency in accelerating relativistic electrons on the sub-parsec scale. Finally we demonstrate that in order to appease the ravenous hunger of radio loud jets its production must be somehow linked to the dissipation process in the inner part of the disk.

Heino Falcke; Peter L. Biermann

1994-11-23T23:59:59.000Z

Note: This page contains sample records for the topic "radio frequency identification" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

RADIO DETECTION OF THE FERMI-LAT BLIND SEARCH MILLISECOND PULSAR J1311-3430  

SciTech Connect (OSTI)

We report the detection of radio emission from PSR J1311-3430, the first millisecond pulsar (MSP) discovered in a blind search of Fermi Large Area Telescope (LAT) gamma-ray data. We detected radio pulsations at 2 GHz, visible for <10% of {approx}4.5 hr of observations using the Green Bank Telescope (GBT). Observations at 5 GHz with the GBT and at several lower frequencies with Parkes, Nancay, and the Giant Metrewave Radio Telescope resulted in non-detections. We also report the faint detection of a steep spectrum continuum radio source (0.1 mJy at 5 GHz) in interferometric imaging observations with the Jansky Very Large Array. These detections demonstrate that PSR J1311-3430 is not radio quiet and provide additional evidence that radio-quiet MSPs are rare. The radio dispersion measure of 37.8 pc cm{sup -3} provides a distance estimate of 1.4 kpc for the system, yielding a gamma-ray efficiency of 30%, typical of LAT-detected MSPs. We see apparent excess delay in the radio pulses as the pulsar appears from eclipse and we speculate on possible mechanisms for the non-detections of the pulse at other orbital phases and observing frequencies.

Ray, P. S.; Wood, K. S. [Space Science Division, Naval Research Laboratory, Washington, DC 20375-5352 (United States); Ransom, S. M. [National Radio Astronomy Observatory (NRAO), Charlottesville, VA 22903 (United States); Cheung, C. C. [National Academy of Sciences, Washington, DC 20001 (United States); Giroletti, M. [INAF Istituto di Radioastronomia, I-40129 Bologna (Italy); Cognard, I. [Laboratoire de Physique et Chimie de l'Environnement, LPCE UMR 6115 CNRS, F-45071 Orleans Cedex 02 (France); Camilo, F. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Bhattacharyya, B. [Inter-University Centre for Astronomy and Astrophysics, Pune 411 007 (India); Roy, J. [National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Pune 411 007 (India); Romani, R. W.; Kerr, M. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Ferrara, E. C. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Guillemot, L.; Kramer, M. [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, D-53121 Bonn (Germany); Johnston, S.; Keith, M. [CSIRO Astronomy and Space Science, Australia Telescope National Facility, Epping NSW 1710 (Australia); Pletsch, H. J. [Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, D-30167 Hannover (Germany); Saz Parkinson, P. M., E-mail: Paul.Ray@nrl.navy.mil [Santa Cruz Institute for Particle Physics, Department of Physics and Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States)

2013-01-20T23:59:59.000Z

302

Multiple Radios for Fast Rendezvous in Cognitive Radio Networks  

E-Print Network [OSTI]

--cognitive radio, blind rendezvous, channel hopping ! 1 INTRODUCTION WITH the traditional static spectrum managemen- t, a significant portion of the licensed spectrum is underutilized in most of time while the unlicensed spectrum is over-crowded due to the growing de- mand for wireless radio spectrum from exponen

Chu, Xiaowen

303

Multiple Radios for Effective Rendezvous in Cognitive Radio Networks  

E-Print Network [OSTI]

portions of the spectrum of the licensed users (or primary users, PUs). In cognitive radio networks (CRNs With the traditional static spectrum management, a majority of the licensed spectrum is underutilized in most of time while the unlicensed spectrum is over-crowded due to the growing demand for wireless radio spectrum from

Chu, Xiaowen

304

Prediction of Fast Fading Mobile Radio Channels in Wideband Communication Systems  

E-Print Network [OSTI]

Prediction of Fast Fading Mobile Radio Channels in Wideband Communication Systems Liang Dong on the performance of wireless communication systems, such that the prediction of the changing channel behaviors-frequency prediction scheme has superior performance over conducting the channel predic- tion on a single frequency. I

Dong, Liang

305

Multiphase turbulent interstellar medium: some recent results from radio astronomy  

E-Print Network [OSTI]

The radio frequency 1.4 GHz transition of the atomic hydrogen is one of the important tracers of the diffuse neutral interstellar medium. Radio astronomical observations of this transition, using either a single dish telescope or an array interferometer, reveal different properties of the interstellar medium. Such observations are particularly useful to study the multiphase nature and turbulence in the interstellar gas. Observations with multiple radio telescopes have recently been used to study these two closely related aspects in greater detail. Using various observational techniques, the density and the velocity fluctuations in the Galactic interstellar medium was found to have a Kolmogorov-like power law power spectra. The observed power law scaling of the turbulent velocity dispersion with the length scale can be used to derive the true temperature distribution of the medium. Observations from a large ongoing atomic hydrogen absorption line survey have also been used to study the distribution of gas at d...

Roy, Nirupam

2015-01-01T23:59:59.000Z

306

On the origin of radio emission in radio quiet quasars  

E-Print Network [OSTI]

The radio emission in radio loud quasars originates in a jet carrying relativistic electrons. In radio quiet quasars (RQQs) the relative radio emission is ~10^3 times weaker, and its origin is not established yet. We show here that there is a strong correlation between the radio luminosity (L_R) and X-ray luminosity (L_X) with L_R~10^-5L_X, for the radio quiet Palomar-Green (PG) quasar sample. The sample is optically selected, with nearly complete radio and X-ray detections, and thus this correlation cannot be due to direct selection biases. The PG quasars lie on an extension of a similar correlation noted by Panessa et al., for a small sample of nearby low luminosity type 1 AGN. A remarkably similar correlation, known as the Guedel-Benz relation, where L_R/L_X~10^-5, holds for coronally active stars. The Guedel-Benz relation, together with correlated stellar X-ray and radio variability, implies that the coronae are magnetically heated. We therefore raise the possibility that AGN coronae are also magnetically heated, and that the radio emission in RQQ also originates in coronal activity. If correct, then RQQ should generally display compact flat cores at a few GHz due to synchrotron self-absorption, while at a few hundred GHz we should be able to see directly the X-ray emitting corona, and relatively rapid and large amplitude variability, correlated with the X-ray variability, is likely to be seen. We also discuss possible evidence that the radio and X-ray emission in ultra luminous X-ray sources and Galactic black holes may be of coronal origin as well.

Ari Laor; Ehud Behar

2008-08-05T23:59:59.000Z

307

Cluster Mergers and Diffuse Radio Emission in Abell 2256 and Abell 754  

E-Print Network [OSTI]

We present deep VLA observations of the galaxy clusters Abell 2256 and Abell 754, both of which appear to be in the violent stage of major cluster merger events. The complex nature of Abell 2256 is revealed through radio images which, in addition to the head-tail galaxies, show two extended, irregular, and sharp-edged regions of diffuse radio emission at the cluster periphery (so called radio relics), and a large-scale diffuse radio halo located in the central regions of the cluster. Polarimetry of the A2256 cluster relics reveals large-scale ordered magnetic fields which appear to trace the bright filaments in the relics. The polarization fraction across the relics ranges from 20% - 40% with the majority of the relics polarized above the 30% level. At the sensitivity of our current observations we place an upper limit of 20% on the polarization of the radio halo. Low frequency VLA observations of Abell 754 reveal extended, diffuse radio (halo) emission in the cluster core region as well as steep spectrum emission in the cluster periphery. The location, morphology, and spectral index of the peripheral emission are consistent with the properties of radio relics. The X-ray evidence of the ongoing mergers in both clusters, together with the polarization properties of A2256's radio relics supports recent suggestions of a merger-induced origin of the relic emission. Deciphering the complex radio properties of these clusters may thus provide the key to understanding the dynamical history of the systems.

T. E. Clarke; T. A. Ensslin

2001-06-07T23:59:59.000Z

308

ISM band to U-NII band frequency transverter and method of frequency transversion  

DOE Patents [OSTI]

A frequency transverter (10) and method for enabling bi-frequency dual-directional transfer of digitally encoded data on an RF carrier by translating between a crowded or otherwise undesirable first frequency band, such as the 2.4 GHz ISM band, and a less-crowded or otherwise desirable second frequency band, such as the 5.0 GHz-6.0 GHz U-NII band. In a preferred embodiment, the transverter (10) connects between an existing data radio (11) and its existing antenna (30), and comprises a bandswitch (12); an input RF isolating device (14); a transmuter (16); a converter (18); a dual output local oscillator (20); an output RF isolating device (22); and an antenna (24) tuned to the second frequency band. The bandswitch (12) allows for bypassing the transverter (10), thereby facilitating its use with legacy systems. The transmuter (14) and converter (16) are adapted to convert to and from, respectively, the second frequency band.

Stepp, Jeffrey David (Grandview, MO); Hensley, Dale (Grandview, MO)

2006-04-04T23:59:59.000Z

309

Resonant circuit which provides dual-frequency excitation for rapid cycling of an electromagnet  

DOE Patents [OSTI]

Disclosed is a novel ring-magnet control circuit that permits synchrotron repetition rates much higher than the frequency of the sinusoidal guide field of the ring magnet during particle acceleration. The control circuit generates sinusoidal excitation currents of different frequencies in the half waves. During radio-frequency acceleration of the synchrotron, the control circuit operates with a lower frequency sine wave and, thereafter, the electromagnets are reset with a higher-frequency half sine wave.

Praeg, W.F.

1982-03-09T23:59:59.000Z

310

IEEE PHOTONICS TECHNOLOGY LETTERS 1 Remote Optoelectronic Frequency Down-Conversion  

E-Print Network [OSTI]

IEEE PHOTONICS TECHNOLOGY LETTERS 1 Remote Optoelectronic Frequency Down-Conversion Using 60-GHz Kim, Associate Member, IEEE Abstract--A new optoelectronic frequency down-conversion method for radio local oscillator signals. Using this optoelectronic frequency down-converter, an RoF uplink

Choi, Woo-Young

311

Attenuation of radio signals by the ionosphere of Mars: Theoretical  

E-Print Network [OSTI]

radio frequency and peak electron density Molina-Cuberos et al. (2002) #12;Power loss equation · Effects solution #12;Power loss at 1, 10, 100, 1000 MHz 1 MHz, 64 km 100 MHz, 29 km 1 GHz, 12 km 10 MHz, 47 km f · Thus P > 1 dB only for f power loss from main ionospheric layer if NXC > 2E10 m-3

Withers, Paul

312

ATLBS EXTENDED SOURCE SAMPLE: THE EVOLUTION IN RADIO SOURCE MORPHOLOGY WITH FLUX DENSITY  

SciTech Connect (OSTI)

Based on the Australia Telescope Low Brightness Survey (ATLBS) we present a sample of extended radio sources and derive morphological properties of faint radio sources. One hundred nineteen radio galaxies form the ATLBS Extended Source Sample (ATLBS-ESS) consisting of all sources exceeding 30'' in extent and integrated flux densities exceeding 1 mJy. We give structural details along with information on galaxy identifications and source classifications. The ATLBS-ESS, unlike samples with higher flux-density limits, has almost equal fractions of FR-I and FR-II radio galaxies, with a large fraction of the FR-I population exhibiting 3C31-type structures. Significant asymmetry in lobe extents appears to be a common occurrence in the ATLBS-ESS FR-I sources compared with FR-II sources. We present a sample of 22 FR-Is at z > 0.5 with good structural information. The detection of several giant radio sources, with size exceeding 0.7 Mpc, at z > 1 suggests that giant radio sources are not less common at high redshifts. The ESS also includes a sample of 28 restarted radio galaxies. The relative abundance of dying and restarting sources is indicative of a model where radio sources undergo episodic activity in which an active phase is followed by a brief dying phase that terminates with restarting of the central activity; in any massive elliptical a few such activity cycles wherein adjacent events blend may constitute the lifetime of a radio source and such bursts of blended activity cycles may be repeated over the age of the host. The ATLBS-ESS includes a 2 Mpc giant radio galaxy with the lowest surface brightness lobes known to date.

Saripalli, L.; Subrahmanyan, R.; Thorat, K.; Ekers, R. D. [Raman Research Institute, C. V. Raman Avenue, Sadashivanagar, Bangalore 560080 (India); Hunstead, R. W.; Johnston, H. M.; Sadler, E. M., E-mail: lsaripal@rri.res.in [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia)

2012-04-01T23:59:59.000Z

313

Cognitive Radio Technology [from THE GUEST EDITORS  

E-Print Network [OSTI]

Cognitive Radio Technology [from THE GUEST EDITORS] Maria Gabriella di Benedetto, Yingbo Hua of cognitive radio. Perhaps the most pressing of them is improved utilization of the electromagnetic radio addressing a multitude of cognitive radio topics were recently approved with a total budget of more than 50

Di Benedetto, Maria-Gabriella

314

Spectrum Sensing and Reconstruction for Cognitive Radio  

E-Print Network [OSTI]

Spectrum Sensing and Reconstruction for Cognitive Radio Amanpreet S Saini, Zhen Hu, Robert Qiu with spectrum sensing and spectrum reconstruction under the umbrella of cognitive radio which is the smart radio to explore and exploit the free spectrum. Spectrum analyzer is used to emulate cognitive radio to do spectrum

Qiu, Robert Caiming

315

NATIONAL RADIO ASTRONOMY OBSERVATORY Green Bank, West Virginia  

E-Print Network [OSTI]

was chosen and thus noise on the BCD data lines causes only a temporary error. General Binary Coded Decimal Standard Identification Data is recorded as Binary Coded Decimal numbers. A standard frequency could location and the Binary-Coded Deci- mal Time Signals transmitted to the scopes. The second system

Groppi, Christopher

316

The radio relic in Abell 2256: overall spectrum and implications for electron acceleration  

E-Print Network [OSTI]

The galaxy cluster Abell 2256 hosts one of the most intriguing examples in the class of radio relics. It has been found that this radio relic has a rather flat integrated spectrum at low frequencies that would imply an injection spectral index for the electrons that is inconsistent with the flattest allowed by the test particle diffusive shock acceleration (DSA). We performed new high-frequency observations at 2273, 2640, and 4850 MHz. Combining these new observations with images available in the literature, we constrain the radio integrated spectrum of the radio relic in Abell 2256 over the widest sampled frequency range collected so far for this class of objects (63 -10450 MHz). Moreover, we used X-ray observations of the cluster to check the temperature structure in the regions around the radio relic. We find that the relic keeps an unusually flat behavior up to high frequencies. Although the relic integrated spectrum between 63 and 10450 MHz is not inconsistent with a single power law with $\\alpha_{63}^{1...

Trasatti, M; Lovisari, L; Klein, U; Bonafede, A; Brüggen, M; Dallacasa, D; Clarke, Tracy

2014-01-01T23:59:59.000Z

317

A procedure for oscillatory parameter identification  

SciTech Connect (OSTI)

A procedure is proposed where a power system is excited with a low-level pseduo-random probing signal and the frequency, damping, magnitude, and shape of oscillatory modes are identified using spectral density estimation and frequency-domain transfer-function identification. Attention is focussed on identifying system modes in the presence of noise. Two examples cases are studied: identification of electromechanical oscillation modes in a 16-machine power system; and turbine-generator shaft modes of a 3-machine power plant feeding a series-compensated 500-kV network.

Trudnowski, D.J.; Donnelly, M.K. [Pacific Northwest Lab., Richland, WA (United States); Hauer, J.F. [Bonneville Power Administration, Portland, OR (United States)

1994-02-01T23:59:59.000Z

318

Identification of dynamic force coefficients of a labyrinth and gas damper seal using impact load excitations  

E-Print Network [OSTI]

, and the seal displacement and acceleration time responses in two orthogonal directions are measured. A frequency domain parameter identification procedure allows the determination of the seals' dynamic force coefficients over a frequency range. Tests are made...

Ransom, David Lawrence

1997-01-01T23:59:59.000Z

319

The Late-Time Radio Spectrum of SN1993J  

E-Print Network [OSTI]

We present VLA radio continuum measurements of SN1993J in M81 at the frequencies of 0.32 (P-band), 1.3 and 1.7 (L-band), 4.9 (C-band), 8.5 (X-band), and 14.9 (U-band) GHz carried out on December 17 and 21, 2000, about 2820 days after the supernova explosion. We find that a power-law spectrum, free-free absorbed by an homogeneous, or clumpy, distribution of ionized gas yields the best fit to the radio data. A combined homogeneous-clumpy model is not favored, but neither totally excluded. This result contrasts with the modeling of the early ($t \\lessim $230 days) radio emission from SN1993J, where a mixture of homogeneous and clumpy absorbers appeared to be necessary to adequately describe the behavior of the light curves. The radio spectrum of supernova SN1993J between 0.32 and 14.9 GHz is well characterized by $\\alpha = -0.67 \\pm 0.02 $ ($S_\

M. A. Perez-Torres; A. Alberdi; J. M. Marcaide

2002-05-14T23:59:59.000Z

320

MODELING OF GYROSYNCHROTRON RADIO EMISSION PULSATIONS PRODUCED BY MAGNETOHYDRODYNAMIC LOOP OSCILLATIONS IN SOLAR FLARES  

SciTech Connect (OSTI)

A quantitative study of the observable radio signatures of the sausage, kink, and torsional magnetohydrodynamic (MHD) oscillation modes in flaring coronal loops is performed. Considering first non-zero order effect of these various MHD oscillation modes on the radio source parameters such as magnetic field, line of sight, plasma density and temperature, electron distribution function, and the source dimensions, we compute time-dependent radio emission (spectra and light curves). The radio light curves (of both flux density and degree of polarization) at all considered radio frequencies are then quantified in both time domain (via computation of the full modulation amplitude as a function of frequency) and in Fourier domain (oscillation spectra, phases, and partial modulation amplitude) to form the signatures specific to a particular oscillation mode and/or source parameter regime. We found that the parameter regime and the involved MHD mode can indeed be distinguished using the quantitative measures derived in the modeling. We apply the developed approach to analyze radio burst recorded by Owens Valley Solar Array and report possible detection of the sausage mode oscillation in one (partly occulted) flare and kink or torsional oscillations in another flare.

Mossessian, George; Fleishman, Gregory D. [Center For Solar-Terrestrial Research, New Jersey Institute of Technology, Newark, NJ 07102 (United States)

2012-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "radio frequency identification" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

A Combined EIS-NVSS Survey Of Radio Sources (CENSORS) III: Spectroscopic observations  

E-Print Network [OSTI]

The Combined EIS-NVSS Survey Of Radio Sources (CENSORS) is a 1.4GHz radio survey selected from the NRAO VLA Sky Survey (NVSS) and complete to a flux-density of 7.2mJy. It targets the ESO Imaging Survey (EIS) Patch D, which is a 3 by 2 square degree field centred on 09 51 36.0, -21 00 00 (J2000). This paper presents the results of spectroscopic observations of 143 of the 150 CENSORS sources. The primary motivation for these observations is to achieve sufficient spectroscopic completeness so that the sample may be used to investigate the evolution of radio sources. The observations result in secure spectroscopic redshifts for 63% of the sample and likely redshifts (based on a single emission line, for example) for a further 8%. Following the identification of the quasars and star-forming galaxies in the CENSORS sample, estimated redshifts are calculated for the remainder of the sample via the K-z relation for radio galaxies. Comparison of the redshift distribution of the CENSORS radio sources to distributions predicted by the various radio luminosity function evolution models of Dunlop & Peacock 1990, results in no good match. This demonstrates that this sample can be used to expand upon previous work in that field.

M. H. Brookes; P. N. Best; J. A. Peacock; H. J. A. Rottgering; J. S. Dunlop

2008-02-08T23:59:59.000Z

322

Blind Identification of MIMO FIR Systems Driven by Quasi-Stationary Sources Using Second Order  

E-Print Network [OSTI]

1 Blind Identification of MIMO FIR Systems Driven by Quasi-Stationary Sources Using Second Order This paper discusses a frequency domain method for blind identification of MIMO convolutive channels driven are presented to demonstrate the performance of the new algorithm1 . I. Introduction Blind identification

Reilly, James P.

323

Towards Cognitive Radio Networks: Spectrum Utilization Measurements in Suburb Environment  

E-Print Network [OSTI]

Towards Cognitive Radio Networks: Spectrum Utilization Measurements in Suburb Environment Václav in an opportunistic way. Cognitive radio concept for better spectrum utilization is introduced here along -- Cognitive radio, radio spectrum management, spectrum sensing, spectrum utilization. I. INTRODUCTION

Paris-Sud XI, Université de

324

THE 5 GHz ARECIBO SEARCH FOR RADIO FLARES FROM ULTRACOOL DWARFS  

SciTech Connect (OSTI)

We present the results of a 4.75 GHz survey of 33 brown dwarfs and one young exoplanetary system for flaring radio emission, conducted with the 305 m Arecibo radio telescope. The goal of this program was to detect and characterize the magnetic fields of objects cooler than spectral type L3.5, the coolest brown dwarf detected prior to our survey. We have also attempted to detect flaring radio emission from the HR 8799 planetary system, guided by theoretical work indicating that hot, massive exoplanets may have strong magnetic fields capable of generating radio emission at GHz frequencies. We have detected and confirmed radio flares from the T6.5 dwarf 2MASS J10475385+2124234. This detection dramatically extends the temperature range over which brown dwarfs appear to be at least sporadic radio-emitters, from 1900 K (L3.5) down to 900 K (T6.5). It also demonstrates that the utility of radio detection as a unique tool to study the magnetic fields of substellar objects extends to the coolest dwarfs, and, plausibly to hot, massive exoplanets. We have also identified a single, 3.6{sigma} flare from the L1 dwarf, 2MASS J1439284+192915. This detection is tentative and requires confirmation by additional monitoring observations.

Route, Matthew; Wolszczan, Alexander, E-mail: mroute@astro.psu.edu, E-mail: alex@astro.psu.edu [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States)

2013-08-10T23:59:59.000Z

325

AN ULTRA-STEEP-SPECTRUM RADIO RELIC IN THE GALAXY CLUSTER A2443  

SciTech Connect (OSTI)

We present newly discovered radio emission in the galaxy cluster A2443 which (1) is diffuse, (2) has an extremely steep spectrum, (3) is offset from the cluster center, (4) is of irregular morphology, and (5) is not clearly associated with any of the galaxies within the cluster. The most likely explanation is that this emission is a cluster radio relic associated with a cluster merger. We present deep observations of A2443 at multiple low frequencies (1425, 325, and 74 MHz) which help characterize the spectrum and morphology of this relic. Based on the curved spectral shape of the relic emission and the presence of small-scale structure, we suggest that this new source is likely a member of the radio phoenix class of radio relics.

Cohen, A. S.; Clarke, T. E., E-mail: aaron_cohen@alum.mit.edu [Naval Research Laboratory, Code 7213, Washington, DC 20375 (United States)

2011-05-15T23:59:59.000Z

326

Some Comments related to AGN Radio Loudness  

E-Print Network [OSTI]

The bimodality of the AGN radio loudness distribution, and the relation of radio loudness and black hole mass were recently disputed. A closer look at the existing data suggests possible resolutions of these disputes, as further described below.

Ari Laor

2003-12-24T23:59:59.000Z

327

Peptide identification  

DOE Patents [OSTI]

Peptides are identified from a list of candidates using collision-induced dissociation tandem mass spectrometry data. A probabilistic model for the occurrence of spectral peaks corresponding to frequently observed partial peptide fragment ions is applied. As part of the identification procedure, a probability score is produced that indicates the likelihood of any given candidate being the correct match. The statistical significance of the score is known without necessarily having reference to the actual identity of the peptide. In one form of the invention, a genetic algorithm is applied to candidate peptides using an objective function that takes into account the number of shifted peaks appearing in the candidate spectrum relative to the test spectrum.

Jarman, Kristin H [Richland, WA; Cannon, William R [Richland, WA; Jarman, Kenneth D [Richland, WA; Heredia-Langner, Alejandro [Richland, WA

2011-07-12T23:59:59.000Z

328

DISCOVERY OF THE DISTURBED RADIO MORPHOLOGY IN THE INTERACTING BINARY QUASAR FIRST J164311.3+315618  

SciTech Connect (OSTI)

We report the high-resolution radio observations and the subsequent analysis of the radio-loud compact steep spectrum quasar FIRST J164311.3+315618, one of the members of a binary system. The second component of the system is a radio-quiet active galactic nucleus. The projected separation of this pair is 2.''3 (15 kpc); it is one of the smallest-known-separation binary quasars. The multi-band images of this binary system made with the Hubble Space Telescope show that the host galaxy of the radio-loud quasar is highly disturbed. The radio observations presented here were made with the Multi-Element Radio-Linked interferometer network (MERLIN) at 1.66 GHz and 5 GHz. We show that the radio morphology of FIRST J164311.3+315618 is complex on both frequencies and exhibits four components that indicate the intermittent activity with a possible rapid change of the jet direction and/or restarting of the jet due to the interaction with the companion. The radio components that are no longer powered by the jet can quickly fade away. We suggest that this makes the potential distortions of the radio structure short-lived phenomena. Our numerical simulations show that the influence of the companion can lead to prolonged current and future activities. FIRST J164311.3+315618 is an unusual and statistically very rare low redshift binary quasar wherein the first close encounter is probably just taking place.

Kunert-Bajraszewska, Magdalena [Torun Centre for Astronomy, Nicolaus Copernicus University, 87-100 Torun (Poland); Janiuk, Agnieszka, E-mail: magda@astro.uni.torun.pl [Center for Theoretical Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, 02-668 Warsaw (Poland)

2011-08-01T23:59:59.000Z

329

RADIO SEARCH FOR H{sub 2}CCC TOWARD HD 183143 AS A CANDIDATE FOR A DIFFUSE INTERSTELLAR BAND CARRIER  

SciTech Connect (OSTI)

To clarify the authenticity of a recently proposed identification of H{sub 2}CCC (linear-C{sub 3}H{sub 2}) as a diffuse interstellar band (DIB) carrier, we searched for the rotational transition of H{sub 2}CCC at a frequency of 103 GHz toward HD 183143 using the 45 m telescope at the Nobeyama Radio Observatory. Although rms noise levels of 32 mK in the antenna temperature were achieved, detection of H{sub 2}CCC was unsuccessful, producing a 3{sigma} upper limit corresponding to a column density of 2.0 Multiplication-Sign 10{sup 13} cm{sup -2}. The upper limit indicates that the contribution of H{sub 2}CCC to the DIB at 5450 Angstrom-Sign is less than 1/25; thus, it is unlikely that the laboratory bands of the B{sup 1} B{sub 1}-X{sup 1} A{sub 1} transition of H{sub 2}CCC and the DIBs at 5450 Angstrom-Sign (and also 4881 Angstrom-Sign ) toward HD 183143 are related.

Araki, Mitsunori; Yamabe, Hiromichi; Tsukiyama, Koichi [Department of Chemistry, Faculty of Science Division I, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku 162-8601, Tokyo (Japan); Takano, Shuro [Nobeyama Radio Observatory and Department of Astronomical Science, The Graduate University for Advanced Studies (Sokendai), 462-2 Nobeyama, Minamimaki, Minamisaku, Nagano 384-1305 (Japan); Kuze, Nobuhiko, E-mail: araki@rs.kagu.tus.ac.jp [Department of Materials and Life Sciences, Faculty of Science and Technology, Sophia University, 7-1 Kioi-cho, Chiyoda-ku 102-8554, Tokyo (Japan)

2012-07-01T23:59:59.000Z

330

Spectrum Characterization for Opportunistic Cognitive Radio Systems  

E-Print Network [OSTI]

1 Spectrum Characterization for Opportunistic Cognitive Radio Systems Tevfik Y¨ucek and H challenging problems in cognitive radio systems. The spectrum of interest needs to be characterized and unused initial network entry is also discussed as a case study. Index Terms-- Cognitive radio, spectrum sensing

Arslan, HĂĽseyin

331

A limit on the ultra-high-energy neutrino flux from lunar observations with the Parkes radio telescope  

E-Print Network [OSTI]

We report a limit on the ultra-high-energy neutrino flux based on a non-detection of radio pulses from neutrino-initiated particle cascades in the Moon, in observations with the Parkes radio telescope undertaken as part of the LUNASKA project. Due to the improved sensitivity of these observations, which had an effective duration of 127 hours and a frequency range of 1.2-1.5 GHz, this limit extends to lower neutrino energies than those from previous lunar radio experiments, with a detection threshold below 10^20 eV. The calculation of our limit allows for the possibility of lunar-origin pulses being misidentified as local radio interference, and includes the effect of small-scale lunar surface roughness. The targeting strategy of the observations also allows us to place a directional limit on the neutrino flux from the nearby radio galaxy Centaurus A.

Bray, J D; Roberts, P; Reynolds, J E; James, C W; Phillips, C J; Protheroe, R J; McFadden, R A; Aartsen, M G

2015-01-01T23:59:59.000Z

332

NONLINEAR PREDICTION OF MOBILE RADIO CHANNELS: MEASUREMENTS AND MARS MODEL DESIGNS  

E-Print Network [OSTI]

, Sweden (torbjorn.ekman@signal.uu.se) 2 Institute of Communications and Radio­Frequency Engineering typically show that there is little room for prediction of channel properties such as received power a short distance. A common approach is to assume that a large number of horizontal planar waves

333

US researchers make tiny radio from 11:05AM Tuesday January 29, 2008  

E-Print Network [OSTI]

," Rogers said. After they have made the arrays of tubes, he said the rest of the process is very similar to making electronics using conventional silicon chips. The researchers teamed up with radio frequency ©2008, APN Holdings NZ Limited Served by: Laurel Instance: static | 04 Feb 2008 05:36:27 | 1,877 Page 2

Rogers, John A.

334

Wave-wave interactions in solar type III radio bursts  

SciTech Connect (OSTI)

The high time resolution observations from the STEREO/WAVES experiment show that in type III radio bursts, the Langmuir waves often occur as localized magnetic field aligned coherent wave packets with durations of a few ms and with peak intensities well exceeding the strong turbulence thresholds. Some of these wave packets show spectral signatures of beam-resonant Langmuir waves, down- and up-shifted sidebands, and ion sound waves, with frequencies, wave numbers, and tricoherences satisfying the resonance conditions of the oscillating two stream instability (four wave interaction). The spectra of a few of these wave packets also contain peaks at f{sub pe}, 2f{sub pe} and 3 f{sub pe} (f{sub pe} is the electron plasma frequency), with frequencies, wave numbers and bicoherences (computed using the wavelet based bispectral analysis techniques) satisfying the resonance conditions of three wave interactions: (1) excitation of second harmonic electromagnetic waves as a result of coalescence of two oppositely propagating Langmuir waves, and (2) excitation of third harmonic electromagnetic waves as a result of coalescence of Langmuir waves with second harmonic electromagnetic waves. The implication of these findings is that the strong turbulence processes play major roles in beam stabilization as well as conversion of Langmuir waves into escaping radiation in type III radio bursts.

Thejappa, G. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); MacDowall, R. J. [NASA/Goddard Space Flight Center, Greenbelt MD 20771 (United States)

2014-02-11T23:59:59.000Z

335

Detection of the thermal radio continuum emission from the G9.62+0.19-F Hot Core  

E-Print Network [OSTI]

We present new high resolution and high sensitivity multi-frequency VLA radio continuum observations of the G9.62+0.19-F hot molecular core. We detect for the first time faint centimetric radio continuum emission at the position of the core. The centimetric continuum spectrum of the source is consistent with thermal emission from ionised gas. This is the first direct evidence that a newly born massive star is powering the G9.62+0.19-F hot core.

L. Testi; P. Hofner; S. Kurtz; M. Rupen

2000-06-15T23:59:59.000Z

336

Contamination of Cluster Radio Sources in the Measurement of the Thermal Sunyaev-Zel'dovich Angular Power Spectrum  

E-Print Network [OSTI]

We present a quantitative estimate of the confusion of cluster radio halos and galaxies in the measurement of the angular power spectrum of the thermal Sunyaev-Zel'dovich (SZ) effect. To achieve the goal, we use a purely analytic approach to both radio sources and dark matter of clusters by incorporating empirical models and observational facts together with some theoretical considerations. It is shown that the correction of cluster radio halos and galaxies to the measurement of the thermal SZ angular power spectrum is no more than 20% at $l>2000$ for observing frequencies $\

Wei Zhou; Xiang-Ping Wu

2003-09-26T23:59:59.000Z

337

RADIO CONTROL ADC0 (RSSI)  

E-Print Network [OSTI]

5 5 4 4 3 3 2 2 1 1 D D C C B B A A RADIO CONTROL PCLK PDATA PALE RADIO DATA SPI_SCK SPI_MOSI SPI_MISO[0..7] PALE RF_DETECT US_OUT_EN SPI_MISO I2C_CLK I2C_DATA US_DETECT AC+ US_OUT SCK RSTN UART_RXD0/SS PB1/SCK PB2/MOSI PB3/MISO PB4/OC0 PB5/OC1A PB6/OC1B PB7/OC1C PC0/A8 PC1/A9 PC2/A10 PC3/A11 PC4/A12

338

LOW-FREQUENCY OBSERVATIONS OF THE MOON WITH THE MURCHISON WIDEFIELD ARRAY  

SciTech Connect (OSTI)

A new generation of low-frequency radio telescopes is seeking to observe the redshifted 21 cm signal from the epoch of reionization (EoR), requiring innovative methods of calibration and imaging to overcome the difficulties of wide-field low-frequency radio interferometry. Precise calibration will be required to separate the expected small EoR signal from the strong foreground emission at the frequencies of interest between 80 and 300 MHz. The Moon may be useful as a calibration source for detection of the EoR signature, as it should have a smooth and predictable thermal spectrum across the frequency band of interest. Initial observations of the Moon with the Murchison Widefield Array 32 tile prototype show that the Moon does exhibit a similar trend to that expected for a cool thermally emitting body in the observed frequency range, but that the spectrum is corrupted by reflected radio emission from Earth. In particular, there is an abrupt increase in the observed flux density of the Moon within the internationally recognized frequency modulated (FM) radio band. The observations have implications for future low-frequency surveys and EoR detection experiments that will need to take this reflected emission from the Moon into account. The results also allow us to estimate the equivalent isotropic power emitted by the Earth in the FM band and to determine how bright the Earth might appear at meter wavelengths to an observer beyond our own solar system.

McKinley, B.; Briggs, F. [Research School of Astronomy and Astrophysics, Australian National University, Canberra (Australia); Kaplan, D. L. [Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI (United States); Greenhill, L. J.; Bernardi, G.; De Oliveira-Costa, A. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Bowman, J. D. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ (United States); Tingay, S. J.; Gaensler, B. M. [ARC Centre of Excellence for All-Sky Astrophysics (CAASTRO), School of Physics, The University of Sydney, Sydney, NSW (Australia); Oberoi, D. [National Centre for Radio Astrophysics, Tata Institute for Fundamental Research, Pune (India); Johnston-Hollitt, M. [School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington (New Zealand); Arcus, W.; Emrich, D. [International Centre for Radio Astronomy Research, Curtin University, Perth (Australia); Barnes, D. [Center for Astrophysics and Supercomputing, Swinburne University of Technology, Melbourne (Australia); Bunton, J. D. [CSIRO Astronomy and Space Science, Canberra (Australia); Cappallo, R. J.; Corey, B. E. [MIT Haystack Observatory, Westford, MA (United States); Deshpande, A. [Raman Research Institute, Bangalore (India); DeSouza, L. [Sydney Institute for Astronomy, School of Physics, University of Sydney, Sydney (Australia); Goeke, R. [MIT Kavli Institute for Astrophysics and Space Research, Cambridge, MA (United States); and others

2013-01-01T23:59:59.000Z

339

The Host Galaxies of Radio-Loud and Radio-Quiet Quasars  

E-Print Network [OSTI]

I review our knowledge of the properties of the host galaxies of radio-loud and radio-quiet quasars, both in comparison to each other and in the context of the general galaxy population. It is now clear that the hosts of radio-loud and radio-quiet quasars with M_V 10^9 solar masses appears to be a necessary (although perhaps not sufficient) condition for the production of radio jets of sufficient power to produce an FRII radio source within a massive galaxy halo.

James S. Dunlop

2001-03-15T23:59:59.000Z

340

A Type II Radio Burst without a Coronal Mass Ejection  

E-Print Network [OSTI]

Type II radio bursts are thought to be a signature of coronal shocks. In this paper, we analyze a short-lived type II burst that started at 07:40 UT on 2011 February 28. By carefully checking white-light images, we find that the type II radio burst is not accompanied by a coronal mass ejection, only with a C2.4 class flare and narrow jet. However, in the extreme-ultraviolet (EUV) images provided by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO), we find a wave-like structure that propagated at a speed of $\\sim$ 600 km s$^{-1}$ during the burst. The relationship between the type II radio burst and the wave-like structure is in particular explored. For this purpose, we first derive the density distribution under the wave by the differential emission measure (DEM) method, which is used to restrict the empirical density model. We then use the restricted density model to invert the speed of the shock that produces the observed frequency drift rate in the dynamic spectrum. The ...

Su, W; Ding, M D; Chen, P F; Sun, J Q

2015-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "radio frequency identification" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Sources of the Radio Background Considered  

SciTech Connect (OSTI)

We investigate possible origins of the extragalactic radio background reported by the ARCADE 2 collaboration. The surface brightness of the background is several times higher than that which would result from currently observed radio sources. We consider contributions to the background from diffuse synchrotron emission from clusters and the intergalactic medium, previously unrecognized flux from low surface brightness regions of radio sources, and faint point sources below the flux limit of existing surveys. By examining radio source counts available in the literature, we conclude that most of the radio background is produced by radio point sources that dominate at sub {mu}Jy fluxes. We show that a truly diffuse background produced by elections far from galaxies is ruled out because such energetic electrons would overproduce the observed X-ray/{gamma}-ray background through inverse Compton scattering of the other photon fields. Unrecognized flux from low surface brightness regions of extended radio sources, or moderate flux sources missed entirely by radio source count surveys, cannot explain the bulk of the observed background, but may contribute as much as 10%. We consider both radio supernovae and radio quiet quasars as candidate sources for the background, and show that both fail to produce it at the observed level because of insufficient number of objects and total flux, although radio quiet quasars contribute at the level of at least a few percent. We conclude that the most important population for production of the background is likely ordinary starforming galaxies above redshift 1 characterized by an evolving radio far-infrared correlation, which increases toward the radio loud with redshift.

Singal, J.; /KIPAC, Menlo Park /Stanford U.; Stawarz, L.; /KIPAC, Menlo Park /Stanford U. /Jagiellonian U., Astron. Observ.; Lawrence, A.; /Edinburgh U., Inst. Astron. /KIPAC, Menlo Park /Stanford U.; Petrosian, V.; /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., Appl. Phys. Dept.

2011-08-22T23:59:59.000Z

342

First results from the FPGA/NIOS Adaptive FIR Filter Using Linear Prediction Implemented in the AERA Radio Stations to Reduce Narrow Band RFI for Radio Detection of Cosmic Rays  

E-Print Network [OSTI]

The FPGA/NIOS FIR filter based on linear prediction (LP) to suppress radio frequency interference (RFI) has been installed in several radio stations in the Auger Engineering Radio Array (AERA) experiment. AERA observes coherent radio emission from extensive air showers induced by ultra-high-energy cosmic rays to make a detailed study of the development of the electromagnetic part of air showers. Radio signals provide complementary information to that obtained from Auger surface detectors, which are predominantly sensitive to the particle content of an air shower at the surface. The radio signals from air showers are caused by the coherent emission due to geomagnetic and charge-excess processes. These emissions can be observed in the frequency band between 10 - 100 MHz. However, this frequency range is significantly contaminated by narrow-band RFI and other human-made distortions. A FIR filter implemented in the FPGA logic segment of the front-end electronics of a radio sensor significantly improves the signal-to-noise ratio. In this paper we present first results of the efficiency of the adaptive LP FIR filter, deployed in real AERA station on pampas, with a comparison to the currently used IIR notch filter with constant coefficients. The laboratory tests confirms the stability of the filter. Using constant LP coefficients the suppression efficiency remains the same for hours, which corresponds to more than $\\bf 10^{12}$ clock cycles. We compared in real conditions several variants of the LP FIR filter with various lengths and various coefficients widths (due to fixed-point representations in the FPGA logic) with the aim to minimize the power consumption for the radio station while keeping sufficient accuracy for noise reduction.

Zbigniew Szadkowski; D. G?as; C. Timmermans; T. Wijnen for the Pierre Auger Collaboration

2014-06-03T23:59:59.000Z

343

Radio-transparent multi-layer insulation for radiowave receivers  

SciTech Connect (OSTI)

In the field of radiowave detection, enlarging the receiver aperture to enhance the amount of light detected is essential for greater scientific achievements. One challenge in using radio transmittable apertures is keeping the detectors cool. This is because transparency to thermal radiation above the radio frequency range increases the thermal load. In shielding from thermal radiation, a general strategy is to install thermal filters in the light path between aperture and detectors. However, there is difficulty in fabricating metal mesh filters of large diameters. It is also difficult to maintain large diameter absorptive-type filters in cold because of their limited thermal conductance. A technology that maintains cold conditions while allowing larger apertures has been long-awaited. We propose radio-transparent multi-layer insulation (RT-MLI) composed from a set of stacked insulating layers. The insulator is transparent to radio frequencies, but not transparent to infrared radiation. The basic idea for cooling is similar to conventional multi-layer insulation. It leads to a reduction in thermal radiation while maintaining a uniform surface temperature. The advantage of this technique over other filter types is that no thermal links are required. As insulator material, we used foamed polystyrene; its low index of refraction makes an anti-reflection coating unnecessary. We measured the basic performance of RT-MLI to confirm that thermal loads are lowered with more layers. We also confirmed that our RT-MLI has high transmittance to radiowaves, but blocks infrared radiation. For example, RT-MLI with 12 layers has a transmittance greater than 95% (lower than 1%) below 200 GHz (above 4 THz). We demonstrated its effects in a system with absorptive-type filters, where aperture diameters were 200 mm. Low temperatures were successfully maintained for the filters. We conclude that this technology significantly enhances the cooling of radiowave receivers, and is particularly suitable for large-aperture systems. This technology is expected to be applicable to various fields, including radio astronomy, geo-environmental assessment, and radar systems.

Choi, J. [Korea University, Anam-dong Seongbuk-gu, Seoul 136-713 (Korea, Republic of)] [Korea University, Anam-dong Seongbuk-gu, Seoul 136-713 (Korea, Republic of); Ishitsuka, H. [Department of Particle and Nuclear Physics, School of High Energy Accelerator Science, The Graduate University for Advanced Studies (SOKENDAI), Shonan Village, Hayama, Kanagawa 240-0193 (Japan)] [Department of Particle and Nuclear Physics, School of High Energy Accelerator Science, The Graduate University for Advanced Studies (SOKENDAI), Shonan Village, Hayama, Kanagawa 240-0193 (Japan); Mima, S. [Terahertz Sensing and Imaging Team, Terahertz-wave Research Group, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan)] [Terahertz Sensing and Imaging Team, Terahertz-wave Research Group, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Oguri, S., E-mail: shugo@post.kek.jp [Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK), Oho, Tsukuba, Ibaraki 305-0801 (Japan); Takahashi, K. [Terahertz Sensing and Imaging Team, Terahertz-wave Research Group, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan) [Terahertz Sensing and Imaging Team, Terahertz-wave Research Group, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Department of Physics, Tohoku University, Sendai, Miyagi 980-8578 (Japan); Tajima, O. [Department of Particle and Nuclear Physics, School of High Energy Accelerator Science, The Graduate University for Advanced Studies (SOKENDAI), Shonan Village, Hayama, Kanagawa 240-0193 (Japan) [Department of Particle and Nuclear Physics, School of High Energy Accelerator Science, The Graduate University for Advanced Studies (SOKENDAI), Shonan Village, Hayama, Kanagawa 240-0193 (Japan); Institute of Particle and Nuclear Studies, High Energy Accelerator Research Organization (KEK), Oho, Tsukuba, Ibaraki 305-0801 (Japan)

2013-11-15T23:59:59.000Z

344

Processing of superconductive materials and high frequency  

SciTech Connect (OSTI)

We do not know yet if superconductivity will become useful without refrigeration. Now, the superconductors are so different from copper that it is difficult to imagine replacing copper with such a brittle material. Superconductors conduct dc with no loss, ac with small losses, and microwaves in co-axial lines with almost no loss and with no dispersion from dc to the highest frequencies. They will probably allow us to close the gap between radio frequency and infrared optical transmission. Clearly your industry should know some things about where superconductivity may lead us and must consider whether the greater risk is to develop them or to let others try it. There are no easy answers yet.

Smith, J.L.

1987-01-01T23:59:59.000Z

345

Robotic localization of hostile networked radio sources with a directional antenna  

E-Print Network [OSTI]

networks. Imagine a scenario, there is a sensor network deployed by enemy. We dispatch a mobile robot equipped with directional Radio Frequency (RF) antenna to search and destroy the networked radio sources. We need an effective scheme to guide the robot... to take the best guess for each step given the current information and known knowledge. Mathemat- ically, Bayes rule is often used to compute the posterior possibility p(X|d) according to the prior possibility p(X). p(X|d) = etap(d|X)p(X). (3.1) Suppose we...

Hu, Qiang

2007-04-25T23:59:59.000Z

346

Cognitive Radio and Smart Grid Dr. Robert C. Qiu  

E-Print Network [OSTI]

Cognitive Radio and Smart Grid Dr. Robert C. Qiu Professor Wireless Networking Systems Laboratory Presented at IEEE Chapter, Huntsville, AL Email: rqiu@tntech.edu http://iweb.tntech.edu/rqiu #12;Cognitive RadioCognitive Radio 2 2/23/2010 #12;Outline Cognitive Radio Cognitive Radio @ Tennessee Tech

Qiu, Robert Caiming

347

Spectrum Decision for Cognitive Radio Networks.  

E-Print Network [OSTI]

??Cognitive Radio Networks (CRNs) are a key technology suggested to be part of 4G and beyond. The fundamental concept is to let Secondary Users (SUs)… (more)

Yao, Yong; Erman, David

2011-01-01T23:59:59.000Z

348

Compressive Spectrum Sensing for Cognitive Radio Networks.  

E-Print Network [OSTI]

??Spectrum sensing is the most important part in cognitive radios. Wideband spectrum sensing requires high speed and large data samples. It makes sampling process challenging… (more)

Nakarmi, Ukash

2011-01-01T23:59:59.000Z

349

Eastern Frequency Response Study  

SciTech Connect (OSTI)

This study was specifically designed to investigate the frequency response of the Eastern Interconnection that results from large loss-of-generation events of the type targeted by the North American Electric Reliability Corp. Standard BAL-003 Frequency Response and Frequency Bias Setting (NERC 2012a), under possible future system conditions with high levels of wind generation.

Miller, N.W.; Shao, M.; Pajic, S.; D'Aquila, R.

2013-05-01T23:59:59.000Z

350

Unveiling the nature of the unidentified gamma-ray sources VI: gamma-ray blazar candidates in the WISH survey and their radio properties  

E-Print Network [OSTI]

According to the second Fermi LAT Catalog (2FGL), about one third of the gamma-ray sources listed have no assigned counterparts at lower energies. Many statistical methods have been developed to find proper counterparts for these sources. We explore the sky area covered at low radio frequency by Westerbork in the Southern Hemisphere (WISH) survey to search for blazar-like associations among the unidentified gamma-ray sources listed in the 2FGL (UGSs). Searching the WISH and NRAO VLA Sky Survey (NVSS) radio surveys within the positional uncertainty regions of the 2FGL UGSs, we select as gamma-ray blazar candidates the radio sources characterized by flat radio spectra between 352 MHz and 1400 MHz. We propose new gamma-ray blazar associations for eight UGSs and we also discuss their spectral properties at low radio frequencies. We compare the radio flux density distribution of the low radio frequency gamma-ray blazar candidates with that of gamma-ray blazars associated with other methods. We find significant dif...

Nori, M; Massaro, F; D'Abrusco, R; Paggi, A; Tosti, G; Funk, S

2015-01-01T23:59:59.000Z

351

Frequency selective infrared sensors  

SciTech Connect (OSTI)

A frequency selective infrared (IR) photodetector having a predetermined frequency band. The exemplary frequency selective photodetector includes: a dielectric IR absorber having a first surface and a second surface substantially parallel to the first surface; an electrode electrically coupled to the first surface of the dielectric IR absorber; and a frequency selective surface plasmonic (FSSP) structure formed on the second surface of the dielectric IR absorber. The FSSP structure is designed to selectively transmit radiation in the predetermined frequency band that is incident on the FSSP structure substantially independent of the angle of incidence of the incident radiation on the FSSP structure.

Davids, Paul; Peters, David W

2014-11-25T23:59:59.000Z

352

Frequency selective infrared sensors  

DOE Patents [OSTI]

A frequency selective infrared (IR) photodetector having a predetermined frequency band. The exemplary frequency selective photodetector includes: a dielectric IR absorber having a first surface and a second surface substantially parallel to the first surface; an electrode electrically coupled to the first surface of the dielectric IR absorber; and a frequency selective surface plasmonic (FSSP) structure formed on the second surface of the dielectric IR absorber. The FSSP structure is designed to selectively transmit radiation in the predetermined frequency band that is incident on the FSSP structure substantially independent of the angle of incidence of the incident radiation on the FSSP structure.

Davids, Paul; Peters, David W

2013-05-28T23:59:59.000Z

353

Ngociation de spectre dans les rseaux de radio cognitive  

E-Print Network [OSTI]

1 Négociation de spectre dans les réseaux de radio cognitive Rapport de recherche - Juin 2013 ................................................................................................................................... 4 I. Chapitre I : Réseaux de radio cognitive)............................................................................................... 6 I.3 Radio cognitive

Paris-Sud XI, Université de

354

Cognitive Radio Network {swjang, sbahk}@netlab.snu.ac.kr  

E-Print Network [OSTI]

2010 Cognitive Radio Network , , {swjang, sbahk}@netlab.snu.ac.kr Analysis of Average Opportunities in Cognitive Radio Networks Seowoo Jang, Saewoong Bahk INMC, EECS, Seoul National University Cognitive Radio Network . Primary user

Bahk, Saewoong

355

Centralized Collaborative Compressed Sensing of Wideband Spectrum for Cognitive Radios  

E-Print Network [OSTI]

1 Centralized Collaborative Compressed Sensing of Wideband Spectrum for Cognitive Radios Hessam, spectrum sensing, cognitive radio, distri- bution discontinuities, algebraic detection, wideband. I technique for cognitive radio systems which combines algebraic tools and compressive sampling techniques

Paris-Sud XI, Université de

356

Spectrum Auction Framework for Access Allocation in Cognitive Radio Networks  

E-Print Network [OSTI]

1 Spectrum Auction Framework for Access Allocation in Cognitive Radio Networks Gaurav S. Kasbekar does not exist. Index Terms Cognitive Radio Networks, Spectrum Auctions, Algorithms I. INTRODUCTION, Wireless Meteropolitan Area networks etc., demand for radio spectrum is increasing. Currently, spectrum

Sarkar, Saswati

357

Optimal Classifier Based Spectrum Sensing in Cognitive Radio Wireless Systems  

E-Print Network [OSTI]

Optimal Classifier Based Spectrum Sensing in Cognitive Radio Wireless Systems Siddharth Sharma tolerance. General Terms Algorithms, Theory, Reliability. Keywords Cognitive Radio; Cooperative Spectrum Cognitive radio (CR) networks have been proposed as a revolutionary breakthrough to enhance spectrum

Jagannatham, Aditya K.

358

Commercial Mobile Radio Service (WRI CMRS)  

E-Print Network [OSTI]

Commercial Mobile Radio Service (WRI ­ CMRS) Commercial Motor Vehicle Roadside Technology Corridor · Improved safety of CMVs and their operation · Reductions in accidents · Increased productivity and mobility · CMRS ­ Commercial Mobile Radio Services · Includes telematics devices (such as electronic on

359

NATIONAL RADIO ASTRONOMY OBSERVATORY CHARLOTTESVILLE, VIRGINIA  

E-Print Network [OSTI]

No. 186 A PROGRESS REPORT ON JOSEPHSON JUNCTION MIXERS FOR MILLIMETER WAVE RADIO ASTRONOMY D. R. DECKER FEBRUARY 1978 NUMBER OF COPIES: 150 #12;A PROGRESS REPORT ON JOSEPHSON JUNCTION MIXERS FOR MILLIMETER WAVE RADIO ASTRONOMY D. R. Decker ABSTRACT Interest in use of Josephson junction devices

Groppi, Christopher

360

Spectrum Sensing Techniques in Cognitive Radio Communications  

E-Print Network [OSTI]

1 Spectrum Sensing Techniques in Cognitive Radio Communications Mario Bkassiny*, Yang Li, Georges for CR's. Index Terms-- Cognitive radio, cooperative spectrum sensing, dynamic spectrum access, energy, jayaweera, christos}@ece.unm.edu Abstract-- In this paper, we review some of the recent patents on spectrum

Jayaweera, Sudharman K.

Note: This page contains sample records for the topic "radio frequency identification" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Broadband Wireless Cognitive Radio-I  

E-Print Network [OSTI]

spectrum usage! #12;CMPE 591 - Broadband Wireless Networks 6 Cognitive Radio "Cognitive Radio" is the key portions of the spectrum is available and detect the presence of licensed users when a user operates in a licensed band. (Spectrum Sensing) 2. Select the best available channel. (Spectrum Decision) 3. Coordinate

TuĂ°cu, Tuna

362

ROXA: a new multi-frequency selected large sample of blazars with SDSS and 2dF optical spectroscopy  

E-Print Network [OSTI]

Context. Although Blazars are a small fraction of the overall AGN population they are expected to be the dominant population of extragalactic sources in the hard X-ray and gamma-ray bands and have been shown to be the largest contaminant of CMB fluctuation maps. So far the number of known blazars is of the order of several hundreds, but the forthcoming AGILE, GLAST and Planck space observatories will detect several thousand of objects of this type. Aims. In preparation for these missions it is necessary to identify new samples of blazars to study their multi-frequency characteristics and statistical properties. Methods. We compiled a sample of objects with blazar-like properties via a cross-correlation between large radio (NVSS, ATCAPMN) and X- ray surveys (RASS) using the SDSS-DR4 and 2dF survey data to spectroscopically identify our candidates and test the validity of the selection method. Results. We present the Radio - Optical - X-ray catalog built at ASDC (ROXA), a list of 816 objects among which 510 are confirmed blazars. Only 19% of the candidates turned out to be certainly non-blazars demonstrating the high efficiency of our selection method. Conclusions. Our catalog includes 173 new blazar identifications, or about 10% of all presently known blazars. The relatively high flux threshold in the X-ray energy band (given by the RASS survey) preferentially selects objects with high fx / fr ratio leading to the discovery of new High Energy Peaked BL Lac (HBLs). Our catalog therefore includes many new potential targets for GeV-TeV observations.

S. Turriziani; E. Cavazzuti; P. Giommi

2007-05-10T23:59:59.000Z

363

NATIONAL RADIO ASTRONOMY OBSERVATORY GREEN BANK, WEST VIRGINIA  

E-Print Network [OSTI]

NATIONAL RADIO ASTRONOMY OBSERVATORY GREEN BANK, WEST VIRGINIA ELECTRONICS DIVISION TECHNICAL NOTE R. Lacasse #12;NATIONAL RADIO ASTRONOMY OBSERVATORY Green Bank, West Virginia 140-ft CASSEGRAIN BAa

Groppi, Christopher

364

Frequency and amplitude control for an experimental linac rf drive  

E-Print Network [OSTI]

, India Chair of Advisory Committee: Dr. S. P. Bhattacharyya, The Texas Accelerator Center (TAC) experimental linear accelerator uses a radio- frequency quadrupole (RFQ) to accelerate a 10 mA beam of H ions to 500 keV. It is to be used as an injector... to form a high-energy input beam for large circular accelerators. The pulsed beam will require 100 kW peak rf power at 473 MHz. To satisfy the beam dynamics requirements for particle acceleration and to minimize beam spill, the frequency of the source...

Atre, Mahesh Purushottam

1992-01-01T23:59:59.000Z

365

OPTICAL SPECTRA OF CANDIDATE INTERNATIONAL CELESTIAL REFERENCE FRAME (ICRF) FLAT-SPECTRUM RADIO SOURCES  

SciTech Connect (OSTI)

Continuing our program of spectroscopic observations of International Celestial Reference Frame (ICRF) sources, we present redshifts for 120 quasars and radio galaxies. Data were obtained with five telescopes: the 3.58 m European Southern Observatory New Technology Telescope, the two 8.2 m Gemini telescopes, the 2.5 m Nordic Optical Telescope (NOT), and the 6.0 m Big Azimuthal Telescope of the Special Astrophysical Observatory in Russia. The targets were selected from the International VLBI Service for Geodesy and Astrometry candidate International Celestial Reference Catalog which forms part of an observational very long baseline interferometry (VLBI) program to strengthen the celestial reference frame. We obtained spectra of the potential optical counterparts of more than 150 compact flat-spectrum radio sources, and measured redshifts of 120 emission-line objects, together with 19 BL Lac objects. These identifications add significantly to the precise radio-optical frame tie to be undertaken by Gaia, due to be launched in 2013, and to the existing data available for analyzing source proper motions over the celestial sphere. We show that the distribution of redshifts for ICRF sources is consistent with the much larger sample drawn from Faint Images of the Radio Sky at Twenty cm (FIRST) and Sloan Digital Sky Survey, implying that the ultra-compact VLBI sources are not distinguished from the overall radio-loud quasar population. In addition, we obtained NOT spectra for five radio sources from the FIRST and NRAO VLA Sky Survey catalogs, selected on the basis of their red colors, which yielded three quasars with z > 4.

Titov, O.; Stanford, Laura M. [Geoscience Australia, P.O. Box 378, Canberra, ACT 2601 (Australia); Johnston, Helen M.; Hunstead, Richard W. [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia); Pursimo, T. [Nordic Optical Telescope, Nordic Optical Telescope Apartado 474E-38700 Santa Cruz de La Palma, Santa Cruz de Tenerife (Spain); Jauncey, David L. [CSIRO Astronomy and Space Science, ATNF and Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Maslennikov, K. [Central Astronomical Observatory at Pulkovo, Pulkovskoye Shosse, 65/1, 196140, St. Petersburg (Russian Federation); Boldycheva, A., E-mail: oleg.titov@ga.gov.au [Ioffe Physical Technical Institute, 26 Polytekhnicheskaya, St. Petersburg, 194021 (Russian Federation)

2013-07-01T23:59:59.000Z

366

LIMITS ON PROMPT, DISPERSED RADIO PULSES FROM GAMMA-RAY BURSTS  

SciTech Connect (OSTI)

We have searched for prompt radio emission from nine gamma-ray bursts (GRBs) with a 12 m telescope at 1.4 GHz, with a time resolution of 64 {mu}s to 1 s. We detected single dispersed radio pulses with significances >6{sigma} in the few minutes following two GRBs. The dispersion measures of both pulses are well in excess of the expected Galactic values, and the implied rate is incompatible with known sources of single dispersed pulses. The arrival times of both pulses also coincide with breaks in the GRB X-ray light curves. A null trial and statistical arguments rule out random fluctuations as the origin of these pulses with >95% and {approx}97% confidence, respectively, although a simple population argument supports a GRB origin with confidence of only 2%. We caution that we cannot rule out radio frequency interference (RFI) as the origin of these pulses. If the single pulses are not related to the GRBs, we set an upper limit on the flux density of radio pulses emitted between 200 and 1800 s after a GRB of 1.27w {sup -1/2} Jy, where 6.4 Multiplication-Sign 10{sup -5} s < w < 32 Multiplication-Sign 10{sup -3} s is the pulse width. We set a limit of less than 760 Jy for long timescale (>1 s) variations. These limits are some of the most constraining at high time resolution and GHz frequencies in the early stages of the GRB phenomenon.

Bannister, K. W.; Murphy, T.; Gaensler, B. M. [Sydney Institute for Astronomy (SIfA), School of Physics A29, University of Sydney, NSW 2006 (Australia); Reynolds, J. E., E-mail: keith.bannister@csiro.au [CSIRO Astronomy and Space Science, P.O. Box 76, Epping, NSW 1710 (Australia)

2012-09-20T23:59:59.000Z

367

Radio jet emission from GeV-emitting narrow-line Seyfert 1 galaxies  

E-Print Network [OSTI]

We studied the radio emission from four radio-loud and gamma-ray-loud narrow-line Seyfert 1 galaxies. The goal was to investigate whether a relativistic jet is operating at the source, and quantify its characteristics. We relied on the most systematic monitoring of such system in the cm and mm radio bands which is conducted with the Effelsberg 100 m and IRAM 30 m telescopes and covers the longest time-baselines and the most radio frequencies to date. We extract variability parameters and compute variability brightness temperatures and Doppler factors. The jet powers were computed from the light curves to estimate the energy output. The dynamics of radio spectral energy distributions were examined to understand the mechanism causing the variability. All the sources display intensive variability that occurs at a pace faster than what is commonly seen in blazars. The flaring events show intensive spectral evolution indicative of shock evolution. The brightness temperatures and Doppler factors are moderate, imply...

Angelakis, E; Marchili, N; Foschini, L; Myserlis, I; Karamanavis, V; Komossa, S; Blinov, D; Krichbaum, T P; Sievers, A; Ungerechts, H; Zensus, J A

2015-01-01T23:59:59.000Z

368

High-Resolution Radio Imaging of Gravitational Lensing Candidates in the 1 Jansky BL Lac Sample  

E-Print Network [OSTI]

While BL Lacertae objects are widely believed to be highly beamed, low-luminosity radio galaxies, many radio-selected BL Lacs have extended radio power levels and optical emission lines that are too luminous to be low-luminosity radio galaxies. Also, Stocke & Rector discovered an excess of MgII absorption systems along BL Lac sightlines compared to quasars, suggesting that gravitational lensing may be another means of creating the BL Lac phenomenon in some cases. We present a search for gravitationally-lensed BL Lacs with deep, high-resolution, two-frequency VLA radio maps of seven lensing candidates from the 1 Jansky BL Lac sample. We find that none of these objects are resolved into an Einstein ring like B 0218+357, nor do any show multiple images of the core. All of the lensing candidates that were resolved show a flat-spectrum core and very unusual, steep-spectrum extended morphology that is incompatible with a multiply lensed system. Thus, while these observations do not rule out microlensing, no macrolensing is observed.

T. A. Rector; J. T. Stocke

2003-02-19T23:59:59.000Z

369

Frequency Response Analysis Tool  

SciTech Connect (OSTI)

Frequency response has received a lot of attention in recent years at the national level, which culminated in the development and approval of North American Electricity Reliability Corporation (NERC) BAL-003-1 Frequency Response and Frequency Bias Setting Reliability Standard. This report is prepared to describe the details of the work conducted by Pacific Northwest National Laboratory (PNNL) in collaboration with the Bonneville Power Administration and Western Electricity Coordinating Council (WECC) Joint Synchronized Information Subcommittee (JSIS) to develop a frequency response analysis tool (FRAT). The document provides the details on the methodology and main features of the FRAT. The tool manages the database of under-frequency events and calculates the frequency response baseline. Frequency response calculations are consistent with frequency response measure (FRM) in NERC BAL-003-1 for an interconnection and balancing authority. The FRAT can use both phasor measurement unit (PMU) data, where available, and supervisory control and data acquisition (SCADA) data. The tool is also capable of automatically generating NERC Frequency Response Survey (FRS) forms required by BAL-003-1 Standard.

Etingov, Pavel V.; Kosterev, Dmitry; Dai, T.

2014-12-31T23:59:59.000Z

370

THE DIGITAL SYSTEM ARTEMIS FOR REAL-TIME PROCESSING OF RADIO TRANSIENT EMISSIONS IN THE SOLAR CORONA  

E-Print Network [OSTI]

THE DIGITAL SYSTEM ARTEMIS FOR REAL-TIME PROCESSING OF RADIO TRANSIENT EMISSIONS IN THE SOLAR); it is used to process and record the 120 channels of a multichannel solar radiospectrograph in the frequency 30-80 MHz and a two-dimensional multicor- relator interferometer at 75.5 MHz. The large quantity

Athens, University of

371

On the continuum radio-spectrum of Cas A: possible evidence of the non-linear particle acceleration  

E-Print Network [OSTI]

Integrated radio-spectrum of Cas A in continuum was analyzed with special emphasis on possible high frequency spectral curvature. We conclude that the most probable scenario is that Planck's new data reveal the imprint of non-linear particle acceleration in the case of this young Galactic supernova remnant (SNR).

Oni?, D

2015-01-01T23:59:59.000Z

372

VERY LONG BASELINE INTERFEROMETRY OBSERVATIONS OF NGC 6240: RESOLVING THE DOUBLE NUCLEI AND RADIO SUPERNOVAE  

SciTech Connect (OSTI)

The European Very Long Baseline Interferometry (VLBI) Network was used at two epochs in 2003 and 2009 to obtain multi-frequency high-resolution images of the merger galaxy NGC 6240 in order to study the radio properties of all compact high-brightness components in the galaxy. Our observations at milliarcsecond resolution detected the northern and southern nuclei and two radio components, which we interpret as long-lived luminous supernovae associated with circumnuclear starburst activity in the southern nucleus. The new VLBI data support the presence of an active galactic nucleus (AGN) together with starburst activity in the southern nucleus and provide some evidence for an AGN in the northern nucleus. Both nuclei display an inverted spectrum at lower GHz frequencies. The spectrum of the southern nucleus indicates thermal free-free absorption on parsec scales, consistent with the presence of an AGN.

Hagiwara, Yoshiaki [National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, 181-8588 Tokyo (Japan); Baan, Willem A. [ASTRON, P.O. Box 2, 7990 AA Dwingeloo (Netherlands); Kloeckner, Hans-Rainer, E-mail: yoshiaki.hagiwara@nao.ac.jp [Astrophysics, Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom)

2011-07-15T23:59:59.000Z

373

Experimental methodology for non-thermal effects of electromagnetic radiation on biologics  

E-Print Network [OSTI]

Appropriate equipment is needed for research on the effects of radio-frequency radiation from radio-frequency identification (RF-ID) systems on biological materials. In the present study, a complete test system comprising ...

Cox, Felicia C. A. I

2006-01-01T23:59:59.000Z

374

Continuum Radio Emission and Diagnostics  

E-Print Network [OSTI]

and inversely proportional to the square of frequency and to temperature to the power 1.5. It is therefore discusses incoher­ ent emission from thermal plasma in the non­flaring so­ lar atmosphere; other relevant. The opacity of this mecha­ nism is proportional to the product of the electron and ion charge densities

White, Stephen

375

Research Technician Radio Meteor Detection  

E-Print Network [OSTI]

/ULF/VLF frequency range (3 Hz to 30 kHz); (2) pick up naturally-occurring radiation while screening/filtering out a working instrument prototype able to (1) record and store, in digital form, radiation signals in the ELF and recording of radiation thought to originate from meteors in the Earth's upper atmosphere. In addition

376

Microfabricated ion frequency standard  

DOE Patents [OSTI]

A microfabricated ion frequency standard (i.e. an ion clock) is disclosed with a permanently-sealed vacuum package containing a source of ytterbium (Yb) ions and an octupole ion trap. The source of Yb ions is a micro-hotplate which generates Yb atoms which are then ionized by a ultraviolet light-emitting diode or a field-emission electron source. The octupole ion trap, which confines the Yb ions, is formed from suspended electrodes on a number of stacked-up substrates. A microwave source excites a ground-state transition frequency of the Yb ions, with a frequency-doubled vertical-external-cavity laser (VECSEL) then exciting the Yb ions up to an excited state to produce fluorescent light which is used to tune the microwave source to the ground-state transition frequency, with the microwave source providing a precise frequency output for the ion clock.

Schwindt, Peter (Albuquerque, NM); Biedermann, Grant (Albuquerque, NM); Blain, Matthew G. (Albuquerque, NM); Stick, Daniel L. (Albuquerque, NM); Serkland, Darwin K. (Albuquerque, NM); Olsson, III, Roy H. (Albuquerque, NM)

2010-12-28T23:59:59.000Z

377

Blind Equalization and Identification for Differential Space-time Modulated Communication Systems  

E-Print Network [OSTI]

Blind Equalization and Identification for Differential Space-time Modulated Communication Systems A Thesis Presented in Partial Fulfillment of the Requirements for the Degree Master of Science of blind identification and equalization for MIMO system with frequency- selective fading channels. We

Schniter, Philip

378

Utilisation des Protocoles HARQ pour la Radio Cognitive  

E-Print Network [OSTI]

Utilisation des Protocoles HARQ pour la Radio Cognitive Romain Tajan encadré/01/2012 #12;Plan 1 Introduction 2 La Radio Cognitive Techniques de la Radio Cognitive Méthodes d'accès 3 performances du protocole IR-HARQ 4 Utilisation des protocoles HARQ pour la Radio Cognitive Utilisation de l

Dobigeon, Nicolas

379

Energy Efficient Transmissions In MIMO Cognitive Radio Networks  

E-Print Network [OSTI]

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

Huang, Jianwei

380

Spectrum Leasing via Distributed Cooperation in Cognitive Radio  

E-Print Network [OSTI]

Spectrum Leasing via Distributed Cooperation in Cognitive Radio Igor Stanojev1 , Osvaldo Simeone1 for cognitive radio. I. INTRODUCTION Cognitive radio is a debated new paradigm for efficient spectrum or unlicensed model [1], requires secondary users to first sense the radio environment in search of spectrum

Yener, Aylin

Note: This page contains sample records for the topic "radio frequency identification" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Spectrum Leasing via Distributed Cooperation in Cognitive Radio  

E-Print Network [OSTI]

Spectrum Leasing via Distributed Cooperation in Cognitive Radio Igor Stanojev1, Osvaldo Simeone1 for cognitive radio. I. INTRODUCTION Cognitive radio is a debated new paradigm for efficient spectrum or unlicensed model [1], requires secondary users to first sense the radio environment in search of spectrum

Simeone, Osvaldo

382

Collaborative Spectrum Sensing from Sparse Observations in Cognitive Radio Networks  

E-Print Network [OSTI]

1 Collaborative Spectrum Sensing from Sparse Observations in Cognitive Radio Networks Jia (Jasmine for the implementation of cognitive radio. Collaborative spectrum sensing among the cognitive radio nodes is expected to improve the ability of checking complete spectrum usage. Due to hardware limitations, each cognitive radio

Yin, Wotao

383

SAMER: Spectrum Aware Mesh Routing in Cognitive Radio Networks  

E-Print Network [OSTI]

SAMER: Spectrum Aware Mesh Routing in Cognitive Radio Networks SHORT PAPER Ioannis Pefkianakis1 in licensed bands, to meet the increasing demand for radio spectrum. The new open spectrum operation--Cognitive Radio, Spectrum Aware Routing I. INTRODUCTION Cognitive radio networks (CORNET) are an emerging multihop

Lu, Songwu

384

Partial Cooperation for Spectrum Sharing in Cognitive Radio Network  

E-Print Network [OSTI]

Partial Cooperation for Spectrum Sharing in Cognitive Radio Network Lok Man Law1, Fen Hou2, Jianwei that many licensed radio spectrums are heavily under-utilized. Cognitive radio technology can improve spectrum, without affecting the normal communications of the primary licensed users. In cognitive radio

Paris-Sud XI, Université de

385

Partial Cooperation for Spectrum Sharing in Cognitive Radio Network  

E-Print Network [OSTI]

that many licensed radio spectrums are heavily under-utilized. Cognitive radio technology can improve spectrum, without affecting the normal communications of the primary licensed users. In cognitive radioPartial Cooperation for Spectrum Sharing in Cognitive Radio Network Lok Man Law1, Fen Hou2, Jianwei

Huang, Jianwei

386

Cooperative Opportunistic Large Array Approach for Cognitive Radio Networks  

E-Print Network [OSTI]

clearly shows that the licensed radio spectrum is underutilized continuously across time and space [1 to the radio spectrum congestion problem by opportunistic uses of the spectral holes to achieve efficient use created huge demand of radio spectrum. The radio spectrum is a scarce natural resource. Due

Hansen, René Rydhof

387

The nature of the optical---radio correlations for powerful radio galaxies  

E-Print Network [OSTI]

The nature of the optical--radio correlations for powerful radio galaxies is investigated using spectroscopic observations of a complete sample of southern 2Jy radio sources. In line with previous work, we find that significant correlations exist between the luminosities of the [OIII]5007, [OII]3727 and Hbeta emission lines and the radio luminosity. However, our observations are not easily reconciled with the idea that these correlations are caused by the increase in the power of the photoionizing quasar as the jet power increases, with average ISM properties not changing appreciably with redshift or radio power: not only do we find that the scatter in the L_[OIII] vs. L_radio correlation is significantly larger than in L_[OII]} vs. L_radio and L_Hbeta vs. L_radio correlations, but the ionization state deduced from the emission lines does not increase with radio power as predicted by the simple, constant ISM, photionization model. We conclude that: (a) there exists a considerable range in the quasar ionizing luminosity at a given redshift; and (b) that the mean density of the emission line clouds is larger in the high redshift/high power radio sources. The latter density enhancement may either be a consequence of the increased importance of jet-cloud interactions or, alternatively, due to a higher pressure in the confining hot ISM, in the high redshift objects. Deep spectra show that many of the sources in our sample are broad line radio galaxies (BLRG). The fact that the BLRG are observed out the redshift limit of the survey, overlapping in redshift with the quasars, argues against the idea that BLRG are simply the low radio power counterparts of high power, high redshift quasars.

C. N. Tadhunter; R. Morganti; A. Robinson; R. Dickson; M. Villar-Martin; R. A. E. Fosbury

1998-07-23T23:59:59.000Z

388

Optimization of radio astronomical observations using Allan variance measurements  

E-Print Network [OSTI]

Stability tests based on the Allan variance method have become a standard procedure for the evaluation of the quality of radio-astronomical instrumentation. They are very simple and simulate the situation when detecting weak signals buried in large noise fluctuations. For the special conditions during observations an outline of the basic properties of the Allan variance is given, and some guidelines how to interpret the results of the measurements are presented. Based on a rather simple mathematical treatment clear rules for observations in ``Position-Switch'', ``Beam-'' or ``Frequency-Switch'', ``On-The-Fly-'' and ``Raster-Mapping'' mode are derived. Also, a simple ``rule of the thumb'' for an estimate of the optimum timing for the observations is found. The analysis leads to a conclusive strategy how to plan radio-astronomical observations. Particularly for air- and space-borne observatories it is very important to determine, how the extremely precious observing time can be used with maximum efficiency. The analysis should help to increase the scientific yield in such cases significantly.

R. Schieder; C. Kramer

2001-05-04T23:59:59.000Z

389

Identification in Prediction Theory  

E-Print Network [OSTI]

Identification in Prediction Theory Lars B¨aumer Bielefeld 2000 #12;Acknowledgment I wish to thank remarks. 1 #12;Contents 1 Introduction 3 2 Finite-State Predictability 7 2.1 A Universal Predictor Predictability and Identifiability . . . . . . 30 3.3 Markov Machines for Identification

Bielefeld, University of

390

THE COMPACT RADIO STRUCTURE OF RADIO-LOUD NARROW LINE SEYFERT 1 GALAXIES  

SciTech Connect (OSTI)

We present the compact radio structure of three radio-loud narrow line Seyfert 1 galaxies from the Very Long Baseline Array archive data at 2.3, 5, and 8.4 GHz. In RXS J16290+4007, the radio structure is mostly unresolved. The combination of compact radio structure, high brightness temperature, and inverted spectrum between simultaneous 2.3 and 8.4 GHz strongly favors jet relativistic beaming. Combined with the very long baseline interferometry data at 1.6 and 8.4 GHz from the literature, we argue that RXS J16333+4718 also may harbor a relativistic jet, with resolved core-jet structure in 5 GHz. B3 1702+457 is clearly resolved with a well-defined jet component. The overall radio steep spectrum indicates that B3 1702+457 is likely a source optically defined as NLS1 with radio definition of compact steep spectrum sources. From these three sources, we found that radio loud NLS1s can be either intrinsically radio loud (e.g., B3 1702+457) or apparently radio loud due to jet beaming effects (e.g., RXS J16290+4007 and RXS J16333+4718).

Gu Minfeng; Chen Yongjun, E-mail: gumf@shao.ac.c [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030 (China)

2010-06-15T23:59:59.000Z

391

Radio Wavelength Observatories within the Exploration Architecture  

E-Print Network [OSTI]

Observations at radio wavelengths address key problems in astrophysics, astrobiology, and lunar structure including the first light in the Universe (the Epoch of Reionization), the presence of magnetic fields around extrasolar planets, particle acceleration mechanisms, and the structure of the lunar ionosphere. Moreover, achieving the performance needed to address these scientific questions demands observations at wavelengths longer than those that penetrate the Earth's ionosphere, observations in extremely "radio quiet" locations such as the Moon's far side, or both. We describe a series of lunar-based radio wavelength interferometers of increasing capability. The Radio Observatory for Lunar Sortie Science (ROLSS) is an array designed to be deployed during the first lunar sorties (or even before via robotic rovers) and addressing particle acceleration and the lunar ionosphere. Future arrays would be larger, more capable, and deployed as experience is gained in working on the lunar surface.

J. Lazio; R. J. Macdowall; J. Burns; L. Demaio; D. L. Jones; K. W. Weiler

2007-01-26T23:59:59.000Z

392

Public safety radios must pool spectrum  

E-Print Network [OSTI]

The dynamic-spectrum-access research and development community is maturing technologies that will enable radios to share RF spectrum much more intensively. The adoption of DSA technologies by the public-safety community ...

Lehr, William Herndon

393

Radio astronomical polarimetry and phase-coherent matrix convolution  

E-Print Network [OSTI]

A new phase-coherent technique for the calibration of polarimetric data is presented. Similar to the one-dimensional form of convolution, data are multiplied by the response function in the frequency domain. Therefore, the system response may be corrected with arbitrarily high spectral resolution, effectively treating the problem of bandwidth depolarization. As well, the original temporal resolution of the data is retained. The method is therefore particularly useful in the study of radio pulsars, where high time resolution and polarization purity are essential requirements of high-precision timing. As a demonstration of the technique, it is applied to full-polarization baseband recordings of the nearby millisecond pulsar, PSR J0437-4715.

W. van Straten

2001-11-21T23:59:59.000Z

394

EARS (Enhancing Access to the Radio Spectrum) PROGRAM: The radio spectrum is a finite but exceedingly valuable natural resource that  

E-Print Network [OSTI]

EARS (Enhancing Access to the Radio Spectrum) PROGRAM: The radio spectrum is a finite communications, among a multitude of others. During the last two decades, the use of the radio spectrum has on the topic of Enhancing Access to the Radio Spectrum. The charge to the workshop was "to identify

Cetiner, Bedri A.

395

Low Luminosity Radio Loud Active Galactic Nuclei  

E-Print Network [OSTI]

I review observational properties of low power radio loud AGN. High resolution VLBI observations allow the estimate of the jet velocity and orientation with respect to the line of sight and the determination of the Doppler factor. These data reveal rich structures, including two-sided jets and secondary components. New results on 1144+35, a giant radio source with superluminal motion are shown in detail.

G. Giovannini; M. Giroletti

2007-08-30T23:59:59.000Z

396

Variable Frequency Pump Drives  

E-Print Network [OSTI]

-frequency electric motor drive. What is happenin9 with variable frequency driven pun,ps is a classical illustration that evolution in technical products takes place not only because of changes in the processes served by these products, or because of innovations...-pole 3550 rpm squirrel caqe induction motor became available in the early 1930s that high pressure pumps operating at that speed could be buil t. And now, in the 1980s, the development of the solid-state, variable frequency electric motor drive...

Karassik, I. J.; Petraccaro, L. L.; McGuire, J. T.

397

Through-the-earth radio  

DOE Patents [OSTI]

A through-the-earth communication system that includes a digital signal input device; a transmitter operating at a predetermined frequency sufficiently low to effectively penetrate useful distances through-the earth; a data compression circuit that is connected to an encoding processor; an amplifier that receives encoded output from the encoding processor for amplifying the output and transmitting the data to an antenna; and a receiver with an antenna, a band pass filter, a decoding processor, and a data decompressor.

Reagor, David; Vasquez-Dominguez, Jose

2006-12-12T23:59:59.000Z

398

X-Ray Observations of Radio Galaxies  

E-Print Network [OSTI]

We review some of the ways that X-ray observations provide unique information on radio galaxies. Thermal bremsstrahlung X-ray emission provides detailed data on ambient densities and temperatures. These parameters in turn can be used for pressure balance calculations and can demonstrate how the ambient gas affects radio source structure. Additionally, many signatures of the interaction of radio jets and lobes with the hot gas are found in high resolution X-ray maps. Non-thermal X-ray emission from knots and hotspots of radio jets can give us constraints on the relativistic electron population for energies greater that that normally sampled in the radio (in the case of synchrotron emission) or can give us an independent estimate of the average magnetic field strength (if inverse Compton emission is the origin of the X-rays). From recent ROSAT HRI observations of 3C 390.3 and 3C 120, we show evidence that X-ray emission from knots and hotspots appears to be associated with regions of large gradients in the radio surface brightness; i.e. at the location of powerful shocks.

D. E. Harris

1998-04-20T23:59:59.000Z

399

Radio Planetary Nebulae in the Magellanic Clouds  

E-Print Network [OSTI]

We report the extragalactic radio-continuum detection of 15 planetary nebulae (PNe) in the Magellanic Clouds (MCs) from recent Australia Telescope Compact Array+Parkes mosaic surveys. These detections were supplemented by new and high resolution radio, optical and IR observations which helped to resolve the true nature of the objects. Four of the PNe are located in the Small Magellanic Cloud (SMC) and 11 are located in the Large Magellanic Cloud (LMC). Based on Galactic PNe the expected radio flux densities at the distance of the LMC/SMC are up to ~2.5 mJy and ~2.0 mJy at 1.4 GHz, respectively. We find that one of our new radio PNe in the SMC has a flux density of 5.1 mJy at 1.4 GHz, several times higher than expected. We suggest that the most luminous radio PN in the SMC (N S68) may represent the upper limit to radio peak luminosity because it is ~3 times more luminous than NGC 7027, the most luminous known Galactic PN. We note that the optical diameters of these 15 MCs PNe vary from very small (~0.08 pc or ...

Filipovi?, M D; Reid, W A; Payne, J L; Parker, Q A; Crawford, E J; Boji?i?, I S; De Horta, A Y; Hughes, A; Dickel, J; Stootman, F

2009-01-01T23:59:59.000Z

400

Abell 1033: birth of a radio phoenix  

E-Print Network [OSTI]

Extended steep-spectrum radio emission in a galaxy cluster is usually associated with a recent merger. However, given the complex scenario of galaxy cluster mergers, many of the discovered sources hardly fit into the strict boundaries of a precise taxonomy. This is especially true for radio phoenixes that do not have very well defined observational criteria. Radio phoenixes are aged radio galaxy lobes whose emission is reactivated by compression or other mechanisms. Here, we present the detection of a radio phoenix close to the moment of its formation. The source is located in Abell 1033, a peculiar galaxy cluster which underwent a recent merger. To support our claim, we present unpublished Westerbork Synthesis Radio Telescope and Chandra observations together with archival data from the Very Large Array and the Sloan Digital Sky Survey. We discover the presence of two sub-clusters displaced along the N-S direction. The two sub-clusters probably underwent a recent merger which is the cause of a moderately per...

de Gasperin, F; van Weeren, R J; Dawson, W A; Brüggen, M; Bonafede, A; Simionescu, A

2015-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "radio frequency identification" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Multi-frequency aluminum nitride micro-filters for advanced RF communications.  

SciTech Connect (OSTI)

An AlN MEMS resonator technology has been developed, enabling massively parallel filter arrays on a single chip. Low-loss filter banks covering the 10 MHz--10-GHz frequency range have been demonstrated, as has monolithic integration with inductors and CMOS circuitry. The high level of integration enables miniature multi-bandm spectrally aware, and cognitive radios.

Nordquist, Christopher Daniel; Stevens, James E.; Olsson, Roy H., III; Wojciechowski, Kenneth E.; Tuck, Melanie R.

2010-03-01T23:59:59.000Z

402

Progress on the Frequency Agile Solar Radiotelescope T.S. Bastian  

E-Print Network [OSTI]

: coronal magnetography, solar ares and particle acceleration, drivers of space weather, and the thermal the thermal structure and dynamics of the solar chromosphere. In addition to its priority mission as a basicProgress on the Frequency Agile Solar Radiotelescope T.S. Bastian National Radio Astronomy

403

An Optimization of the FPGA Based Wavelet Trigger in Radio Detection of Cosmic Rays  

E-Print Network [OSTI]

Experiments that observe coherent radio emission from extensive air showers induced by ultra-high energy cosmic rays are designed for a detailed study of the development of the electromagnetic part of air showers. Radio detectors can operate with 100% up time as e.g. surface detectors based on water-Cherenkov tanks. They are being developed for ground-based experiments (e.g. the Pierre Auger Observatory) as another type of air shower detector in addition to the fluorescence detectors, which operate with only ~10% of duty in dark nights. The radio signals from air showers are caused by the coherent emission due to geomagnetic radiation and charge excess processes. Currently used self-triggers in radio detectors often generate a dense stream of data, which is analyzed afterwards. Huge amounts of registered data requires a significant man-power for the off-line analysis. An improvement of the trigger efficiency becomes a relevant factor. In this work, Morlet wavelets with various scaling factors were used for an analysis of real data from the Auger Engineering Radio Array and for an optimization of the utilization of the resources in an FPGA. The wavelet analysis showed that the power of events is concentrated mostly in a limited range of the frequency spectrum (consistent with a range imposed by the input analog band-pass filter). However, we found several events with suspicious spectral characteristics, where the signal power is spread over the full band-width sampled by a 200 MHz digitizer with significant contribution of very high and very low frequencies. These events may not origin from cosmic ray showers but can be human-made contaminations. The engine of the wavelet analysis can be implemented into the modern powerful FPGA and can remove suspicious events on-line to reduce the trigger rate.

Zbigniew Szadkowski for the Pierre Auger Collaboration

2014-06-04T23:59:59.000Z

404

A radio-map of the colliding winds in the very massive binary system HD 93129A  

E-Print Network [OSTI]

Radio observations are an effective tool to discover particle acceleration regions in colliding-wind binaries, through detection of synchrotron radiation; these regions are natural laboratories for the study of relativistic particles. Wind-collision region (WCR) models can reproduce the radio continuum spectra of massive binaries that contain both thermal and non-thermal radio emission; however, key constraints for models come from high-resolution imaging. Only five WCRs have been resolved to date at radio frequencies at milliarcsec (mas) angular scales. The source HD 93129A, prototype of the very few known O2 I stars, is a promising target for study: recently, a second massive, early-type star about 50 mas away was discovered, and a non-thermal radio source detected in the region. Preliminary long-baseline array data suggest that a significant fraction of the radio emission from the system comes from a putative WCR. We sought evidence that HD 93129A is a massive binary system with colliding stellar winds tha...

Benaglia, Paula; Moldon, Javier; Nelan, Ed; De Becker, Michael; Dougherty, Sean M; Koribalski, Baerbel

2015-01-01T23:59:59.000Z

405

Mechanically tunable plasma frequency  

E-Print Network [OSTI]

in S12 phases. function [eps, x] = FindPerm(Thru, Sample,It returns the permittivity (eps) and a frequency matrix %0; % Initialize results matrix eps = zeros(n,1); for i = 1:n

Schuil, Crystal Joy

2009-01-01T23:59:59.000Z

406

Graphene Frequency Multipliers  

E-Print Network [OSTI]

In this letter, the ambipolar transport properties of graphene flakes have been used to fabricate full-wave signal rectifiers and frequency-doubling devices. By correctly biasing an ambipolar graphene field-effect transistor ...

Wang, Han

407

1. Identification Number: 2. Program/Project Title: 3. Recipient  

E-Print Network [OSTI]

Personal Property Report Forms Family Other(see special instructions) Frequency Addressees1 1. Identification Number: 2. Program/Project Title: 3. Recipient: 4. Reporting Requirements: A. MANAGEMENT REPORTING Research Performance Progress Report (RPPR) (RD&D Projects) Progress Report (Non

408

Deep Spitzer observations of infrared-faint radio sources: high-redshift radio-loud AGN?  

E-Print Network [OSTI]

Oliver,5 Nick Seymour15 and Jason Surace6 1 CSIRO Australia Telescope National Facility, PO Box 76 Telescope Large Area Survey (ATLAS: Norris et al. 2006) as radio sources with no observable IR counterpart) and Middelberg et al. (2008a) have identified 51 such sources out of 2002 radio sources in the ATLAS survey. So

Norris, Ray

409

The Rapidly Deployable Radio Network  

E-Print Network [OSTI]

frequency is modulated with some information- bearing signal. Beamforming in this case can be described for a generic modulation scheme as follows [14]. Let the signal samples be represented by the vector (2) where is assumed to include the time index...-of-concept system. J. Implementation of RDRN Transmitter Fig. 9 illustrates the configuration of the completed RDRN transmitter. On the right is the interface to the host computer system. At the bottom is a VME rack holding eight IF cards, 698 IEEE JOURNAL...

Evans, Joseph B.; Minden, Gary J.; Shanmugan, K. S.; Prescott, Glenn Eugene; Frost, Victor S.; Ewy, Ben; Sanchez, Ricardo; Sparks, Craig; Malinimohan, K.; Roberts, James A.; Plumb, R. G.; Petr, Dave

1999-04-01T23:59:59.000Z

410

THE DOUBLE PULSAR ECLIPSES. I. PHENOMENOLOGY AND MULTI-FREQUENCY ANALYSIS  

SciTech Connect (OSTI)

The double pulsar PSR J0737-3039A/B displays short, 30 s eclipses that arise around conjunction when the radio waves emitted by pulsar A are absorbed as they propagate through the magnetosphere of its companion pulsar B. These eclipses offer a unique opportunity to directly probe the magnetospheric structure and the plasma properties of pulsar B. We have performed a comprehensive analysis of the eclipse phenomenology using multi-frequency radio observations obtained with the Green Bank Telescope. We have characterized the periodic flux modulations previously discovered at 820 MHz by McLaughlin et al. and investigated the radio frequency dependence of the duration and depth of the eclipses. Based on their weak radio frequency evolution, we conclude that the plasma in pulsar B's magnetosphere requires a large multiplicity factor ({approx}10{sup 5}). We also found that, as expected, flux modulations are present at all radio frequencies in which eclipses can be detected. Their complex behavior is consistent with the confinement of the absorbing plasma in the dipolar magnetic field of pulsar B as suggested by Lyutikov and Thompson and such a geometric connection explains that the observed periodicity is harmonically related to pulsar B's spin frequency. We observe that the eclipses require a sharp transition region beyond which the plasma density drops off abruptly. Such a region defines a plasmasphere that would be well inside the magnetospheric boundary of an undisturbed pulsar. It is also two times smaller than the expected standoff radius calculated using the balance of the wind pressure from pulsar A and the nominally estimated magnetic pressure of pulsar B.

Breton, R. P. [Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4 (Canada); Kaspi, V. M. [Department of Physics, McGill University, Montreal, QC H3A 2T8 (Canada); McLaughlin, M. A. [Department of Physics, West Virginia University, Morgantown, WV 26506 (United States); Lyutikov, M. [Department of Physics, Purdue University, West Lafayette, IN 47907 (United States); Kramer, M. [Max Planck Institut fuer Radioastronomie, Auf dem Huegel 69, 53121 Bonn (Germany); Stairs, I. H. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1 (Canada); Ransom, S. M. [National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States); Ferdman, R. D. [University of Manchester, Jodrell Bank Centre for Astrophysics, Alan Turing Building, Manchester, M13 9PL (United Kingdom); Camilo, F. [Columbia University, New York, NY 10027 (United States); Possenti, A., E-mail: breton@astro.utoronto.ca [INAF-Osservatorio Astronomico di Cagliari, Poggio dei Pini, strada 54, I-09012 Capoterra (Italy)

2012-03-10T23:59:59.000Z

411

Non-linear system identification in flow-induced vibration  

SciTech Connect (OSTI)

The paper introduces a method of identification of non-linear systems encountered in marine engineering applications. The non-linearity is accounted for by a combination of linear subsystems and known zero-memory non-linear transformations; an equivalent linear multi-input-single-output (MISO) system is developed for the identification problem. The unknown transfer functions of the MISO system are identified by assembling a system of linear equations in the frequency domain. This system is solved by performing the Cholesky decomposition of a related matrix. It is shown that the proposed identification method can be interpreted as a {open_quotes}Gram-Schmidt{close_quotes} type of orthogonal decomposition of the input-output quantities of the equivalent MISO system. A numerical example involving the identification of unknown parameters of flow (ocean wave) induced forces on offshore structures elucidates the applicability of the proposed method.

Spanos, P.D.; Zeldin, B.A. [Rice Univ., Houston, TX (United States); Lu, R. [Hudson Engineering Corp., Houston, TX (United States)

1996-12-31T23:59:59.000Z

412

DIAGNOSTICS ON THE SOURCE PROPERTIES OF A TYPE II RADIO BURST WITH SPECTRAL BUMPS  

SciTech Connect (OSTI)

In recent studies, we proposed that source properties of type II radio bursts can be inferred through a causal relationship between the special shape of the type II dynamic spectrum (e.g., bump or break) and simultaneous extreme ultraviolet (EUV)/white light imaging observations (e.g., CME-shock crossing streamer structures). As a further extension of these studies, in this paper we examine the coronal mass ejection (CME) event on 2007 December 31 associated with a multiple type II radio burst. We identify the presence of two spectral bump features on the observed dynamic spectrum. By combining observational analyses of the radio spectral observations and the EUV-white light imaging data, we conclude that the two spectral bumps result from a CME-shock propagating across dense streamers on the southern and northern sides of the CME. It is inferred that the corresponding two type II emissions originate separately from the two CME-shock flanks where the shock geometries are likely quasi-perpendicular or oblique. Since the emission lanes are bumped as a whole within a relatively short time, it suggests that the type II radio bursts with bumps of this study are emitted from spatially confined sources (with a projected lateral dimension smaller than 0.05-0.1 R{sub Sun} at a fundamental frequency level of 20-30 MHz).

Feng, S. W.; Chen, Y.; Kong, X. L.; Li, G.; Song, H. Q. [Institute of Space Sciences and School of Space Science and Physics, Shandong University, Weihai 264209 (China)] [Institute of Space Sciences and School of Space Science and Physics, Shandong University, Weihai 264209 (China); Feng, X. S. [SIGMA Weather Group, State Key laboratory for Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100190 (China)] [SIGMA Weather Group, State Key laboratory for Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100190 (China); Guo, Fan, E-mail: yaochen@sdu.edu.cn [Department of Planetary Sciences and Lunar and Planetary laboratory, University of Arizona, Tucson, AZ 85721 (United States)] [Department of Planetary Sciences and Lunar and Planetary laboratory, University of Arizona, Tucson, AZ 85721 (United States)

2013-04-10T23:59:59.000Z

413

A Combined EIS-NVSS Survey Of Radio Sources II: Infrared imaging and the K-z relation  

E-Print Network [OSTI]

The Combined EIS-NVSS Survey Of Radio Sources (CENSORS) is a 1.4 GHz radio survey selected from the NRAO VLA Sky Survey (NVSS) and complete to a flux-density of 7.2mJy. It targets the ESO Imaging Survey (EIS) Patch D, which is a 3 by 2 square degree field centred on 09 51 36.0 -21 00 00 (J2000). This paper presents K-band imaging of 142 of the 150 CENSORS sources. The primary motivation for beginning infrared imaging of the sample was to identify the host galaxies of the ~30% of sources for which the EIS I-band imaging failed to produce a likely candidate. In addition, K-band magnitudes allow photometric redshift estimation and I - K colours aid the identification of host galaxies (which are typically old, red ellipticals). Of the sources observed in the I and K-bands, four remain undetected, possibly indicating high redshifts for the host galaxies, and eight involve complicated radio structures, or several candidate host galaxies, which have yet to be resolved. Thus, the host galaxy identifications are brought to 92% completeness. In conjunction with spectroscopic observations, the K-band magnitudes have been aperture corrected and used to establish a K-z relation for the CENSORS radio galaxies. This relation is of interest because of its variation, at z > 1, between radio surveys of different flux-density limit. Establishing this relation for CENSORS may shed light on the origin of this variation and will allow an appropriate K-z redshift estimator for any CENSORS source which remains without a spectroscopic redshift. It is shown that whilst the K-z relation for CENSORS is fainter than that of 3CRR at all redshifts, it agrees well with that of 7C over all redshifts studied.

M. H. Brookes; P. N. Best; R. Rengelink; H. J. A. Rottgering

2006-03-27T23:59:59.000Z

414

Extended emission around GPS radio sources  

E-Print Network [OSTI]

Extended radio emission detected around a sample of GHz Peaked Spectrum (GPS) radio sources is discussed. Evidence for extended emission which is related to the GPS source is found in 6 objects out of 33. Three objects are associated with quasars with core-jet pc-scale morphology, and three are identified with galaxies with symmetric (CSO) radio morphology. We conclude that the core-jet GPS quasars are likely to be beamed objects with a continuous supply of energy from the core to the kpc scale. It is also possible that low surface brightness extended radio emission is present in other GPS quasars but the emission is below our detection limit due to the high redshifts of the objects. On the other hand, the CSO/galaxies with extended large scale emission may be rejuvenated sources where the extended emission is the relic of previous activity. In general, the presence of large scale emission associated with GPS galaxies is uncommon, suggesting that in the context of the recurrent activity model, the time scale between subsequent bursts is in general longer than the radiative lifetime of the radio emission from the earlier activity.

C. Stanghellini; C. P. O'Dea; D. Dallacasa; P. Cassaro; S. A. Baum; R. Fanti; C. Fanti

2005-07-21T23:59:59.000Z

415

Molecular gas in nearby powerful radio galaxies  

E-Print Network [OSTI]

We report the detection of CO(1-0) and CO(2-1) emission from the central region of nearby 3CR radio galaxies (z$gas content is below 10$^9$ \\msun. Their individual CO emission exhibit, for 5 cases, a double-horned line profile that is characteristic of an inclined rotating disk with a central depression at the rising part of its rotation curve. The inferred disk or ring distributions of the molecular gas is consistent with the observed presence of dust disks or rings detected optically in the cores of the galaxies. We reason that if their gas originates from the mergers of two gas-rich disk galaxies, as has been invoked to explain the molecular gas in other radio galaxies, then these galaxies must have merged a long time ago (few Gyr or more) but their remnant elliptical galaxies only recently (last 10$^7$ years or less) become active radio galaxies. Instead, we argue the the cannibalism of gas-rich galaxies provide a simpler explanation for the origin of molecular gas in the elliptical hosts of radio galaxies (Lim et al. 2000). Given the transient nature of their observed disturbances, these galaxies probably become active in radio soon after the accretion event when sufficient molecular gas agglomerates in their nuclei.

S. Leon; J. Lim; F. Combes; D. Van-Trung

2001-07-26T23:59:59.000Z

416

Fully Integrated Frequency and Phase Generation for a 6-18GHz Tunable Multi-Band Phased-Array Receiver in CMOS  

E-Print Network [OSTI]

control, phase locked loops, phase noise, phased arrays, radio receivers I. INTRODUCTION Very large-scale phased-arrays covering a wide range of frequencies can provide exciting new opportunities for increasedFully Integrated Frequency and Phase Generation for a 6-18GHz Tunable Multi-Band Phased

Hajimiri, Ali

417

Solar Radio Bursts with Spectral Fine Structures in Preflares  

E-Print Network [OSTI]

A good observation of preflare activities is important for us to understand the origin and triggering mechanism of solar flares, and to predict the occurrence of solar flares. This work presents the characteristics of microwave spectral fine structures as preflare activities of four solar flares observed by Ond\\v{r}ejov radio spectrograph in the frequency range of 0.8--2.0 GHz. We found that these microwave bursts which occurred 1--4 minutes before the onset of flares have spectral fine structures with relatively weak intensities and very short timescales. They include microwave quasi-periodic pulsations (QPP) with very short period of 0.1-0.3 s and dot bursts with millisecond timescales and narrow frequency bandwidths. Accompanying these microwave bursts, there are filament motions, plasma ejection or loop brightening on the EUV imaging observations and non-thermal hard X-ray emission enhancements observed by RHESSI. These facts may reveal certain independent non-thermal energy releasing processes and partic...

Zhang, Yin; Karlický, Marian; Mészárosová, Hana; Huang, Jing; Tan, Chengming; Simőes, Paulo

2014-01-01T23:59:59.000Z

418

Portable Microwave Frequency Dissemination in Free Space and Implications on Ground-Satellite Synchronization  

E-Print Network [OSTI]

Frequency dissemination and synchronization in free space plays an important role in global navigation satellite system (GNSS), radio astronomy and synthetic aperture radar (SAR). In this paper, we demonstrate a portable radio frequency (RF) dissemination scheme via free space using microwave antennas. The setup has a good environment adaptability and high dissemination stability. The frequency signal is disseminated at different distances ranging from 10 to 640 m with a fixed 10 Hz locking bandwidth, and the scaling law of dissemination stability on distance and averaging time is discussed. The preliminary extrapolation shows that the dissemination stability may reach $1\\times10^{-12}/s$ in ground-to-satellite synchronization, which far exceeds all present methods, and is worthy for further study.

Wang, Bo; Bai, Yu; Yuan, Yibo; Gao, Chao; Wang, Lijun

2015-01-01T23:59:59.000Z

419

DISCOVERY OF GIANT RELIC RADIO LOBES STRADDLING THE CLASSICAL DOUBLE RADIO GALAXY 3C452  

SciTech Connect (OSTI)

We report the discovery of a pair of megaparsec size radio lobes of extremely steep spectrum straddling the well-known classical double radio source 3C452. The existence of such fossil lobes was unexpected since for the past several decades this powerful radio galaxy has been regarded as a textbook example of an edge-brightened double radio source of Fanaroff-Riley type II (FR II), which we now show to be a bona fide ''double-double'' radio galaxy (DDRG). Thus, 3C452 presents a uniquely robust example of recurrent nuclear activity in which the restarted jets are expanding non-relativistically within the relic synchrotron plasma from an earlier active phase and hence the inner double fed by them has evolved into a perfectly normal FR II radio source. This situation contrasts markedly with the strikingly narrow inner doubles observed in a few other DDRGs that have been interpreted in terms of compression of the synchrotron plasma of the relic outer lobes at the relativistic bow-shocks driven by the near ballistic propagation of the two inner jets through the relic plasma. A key ramification of this finding is that it cautions against the currently widespread use of FR II classical double radio sources for testing cosmological models and unification schemes for active galactic nuclei.

Sirothia, S. K.; Gopal-Krishna [National Centre for Radio Astrophysics, TIFR, Post Bag No. 3, Pune University Campus, Ganeshkhind, Pune 411 007 (India); Wiita, Paul J., E-mail: sirothia@ncra.tifr.res.in, E-mail: krishna@ncra.tifr.res.in, E-mail: wiitap@tcnj.edu [Department of Physics, College of New Jersey, P.O. Box 7718, Ewing, NJ 08628 (United States)

2013-03-01T23:59:59.000Z

420

Coherent Transition Radiation in Askaryan radio detectors  

E-Print Network [OSTI]

We discuss the coherent transition radiation emitted by a macroscopic bunch of particles with a net charge traversing the boundary of two different media. The obtained expression is compared to the emission from a relativistically moving steady charge, as well the emission from a time-varying charge or current. As a first application, we discuss the transition radiation from high-energy cosmic-ray induced air showers hitting Earth's surface before the cascade has died out in the atmosphere. The induced emission gives rise to a radio signal which should be detectable in the currently operating Askaryan radio detectors built to search for the GZK neutrino flux.

de Vries, Krijn D; van Eijndhoven, Nick; Meures, Thomas; O'Murchadha, Aongus; Scholten, Olaf

2015-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "radio frequency identification" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Location and prediction of storms from measurement of atmospherics at different frequencies  

E-Print Network [OSTI]

the Earth?, Proc. I.R.E., vol. 19, p. 145;: January, 1931. 75. L. W. Austin, "Radio Atmospheric Disturbances and Solar Ac? tivity?, Proc. I.R.E., vol. 15, pp. 837-842; October, 1927. 76. J. K. McNeely and P. J. Konkle, ?Locating Radio Interference... atmospherics from a distant thun? derstorm, with his receiver tuned to 14*6 meters* Many investiga? tions2' C A 8# 9* n * 20* 26' 27* 28 have shown that the atmospher- 29 30ics increase as the frequency is decreased* Mr. Harold Norinder* * and Messers* B* V...

Canterbury, Samuel Luther

1945-01-01T23:59:59.000Z

422

Multiple Objective Fitness Functions for Cognitive Radio Adaptation  

E-Print Network [OSTI]

This thesis explores genetic algorithm and rule-based optimization techniques used by cognitive radios to make operating parameter decisions. Cognitive radios take advantage of intelligent control methods by using sensed ...

Newman, Timothy Ray

2008-04-30T23:59:59.000Z

423

Calculating the probability of detecting radio signals from alien civilizations  

E-Print Network [OSTI]

Although it might not be self-evident, it is in fact entirely possible to calculate the probability of detecting alien radio signals by understanding what types of extraterrestrial radio emissions can be expected and what properties these emissions can have. Using the Drake equation as the obvious starting point, and logically identifying and enumerating constraints of interstellar radio communications can yield the probability of detecting a genuine alien radio signal.

Marko Horvat

2007-07-14T23:59:59.000Z

424

Calculating the probability of detecting radio signals from alien civilizations  

E-Print Network [OSTI]

Although it might not be self-evident, it is in fact entirely possible to calculate the probability of detecting alien radio signals by understanding what types of extraterrestrial radio emissions can be expected and what properties these emissions can have. Using the Drake equation as the obvious starting point, and logically identifying and enumerating constraints of interstellar radio communications can yield the probability of detecting a genuine alien radio signal.

Horvat, Marko

2006-01-01T23:59:59.000Z

425

A RADIO-SELECTED BLACK HOLE X-RAY BINARY CANDIDATE IN THE MILKY WAY GLOBULAR CLUSTER M62  

SciTech Connect (OSTI)

We report the discovery of a candidate stellar-mass black hole in the Milky Way globular cluster M62. We detected the black hole candidate, which we call M62-VLA1, in the core of the cluster using deep radio continuum imaging from the Karl G. Jansky Very Large Array. M62-VLA1 is a faint source with a flux density of 18.7 ± 1.9 ?Jy at 6.2 GHz and a flat radio spectrum (? = –0.24 ± 0.42, for S{sub ?} = ?{sup ?}). M62 is the second Milky Way cluster with a candidate stellar-mass black hole; unlike the two candidate black holes previously found in the cluster M22, M62-VLA1 is associated with a Chandra X-ray source, supporting its identification as a black hole X-ray binary. Measurements of its radio and X-ray luminosity, while not simultaneous, place M62-VLA1 squarely on the well-established radio-X-ray correlation for stellar-mass black holes. In archival Hubble Space Telescope imaging, M62-VLA1 is coincident with a star near the lower red giant branch. This possible optical counterpart shows a blue excess, H? emission, and optical variability. The radio, X-ray, and optical properties of M62-VLA1 are very similar to those for V404 Cyg, one of the best-studied quiescent stellar-mass black holes. We cannot yet rule out alternative scenarios for the radio source, such as a flaring neutron star or background galaxy; future observations are necessary to determine whether M62-VLA1 is indeed an accreting stellar-mass black hole.

Chomiuk, Laura; Ransom, Scott [National Radio Astronomy Observatory, 520 Edgemont Rd, Charlottesville, VA (United States); Strader, Jay [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Maccarone, Thomas J. [Department of Physics, Texas Tech University, Box 41051, Lubbock, TX 79409-1051 (United States); Miller-Jones, James C. A. [International Centre for Radio Astronomy Research, Curtin University, GPO Box U1987, Perth, WA 6845 (Australia); Heinke, Craig [Department of Physics, University of Alberta, 4-183 CCIS, Edmonton, AB T6G 2E1 (Canada); Noyola, Eva [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico (UNAM), A. P. 70-264, 04510 (Mexico); Seth, Anil C., E-mail: chomiuk@pa.msu.edu [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States)

2013-11-01T23:59:59.000Z

426

Jet radio emission in Cygnus X-1 and its orbital modulation  

E-Print Network [OSTI]

We present results of our detailed theoretical study of the observed orbital modulation of the radio emission in Cyg X-1. The modulation occurs due to free-free absorption in the wind from the companion star varying with the orbital phase, and our results put strong constraints on the spatial distribution of the jet radio emission at the frequencies of 2-15 GHz. A crucial role in enhancing the asymmetry of the wind absorption suffered by the jet emission is played by the irradiation by X-rays emitted in the vicinity of the black hole. This increases the wind temperature by more than order of magnitude with respect to that of the wind of an isolated supergiant. The observed phase lags of the minima of the radio emission with respect to the spectroscopic zero phase strongly imply the bulk of the mass of the jet is nonrelativistic (~5 x 10^8 cm/s) within the jet core. The jet can, however, become relativistic outside the core. Also, the jet can have a two-component structure, being slow on the outside and fast inside, in which case its synchrotron-emitting part may be relativistic already in the core. We also consider the observed superorbital modulation of the radio emission (with the period of ~150 d) and find it can be explained by a jet precession both causing variable wind absorption and changing the jet Doppler factor. Finally, we consider the case of Cyg X-3, and show that its lack of observable orbital radio modulation (in spite of strong modulation of X-rays) is explained by that system being both much more compact and much more luminous than Cyg X-1.

A. Szostek; A. A. Zdziarski

2006-12-22T23:59:59.000Z

427

NUCLEAR RADIO JET FROM A LOW-LUMINOSITY ACTIVE GALACTIC NUCLEUS IN NGC 4258  

SciTech Connect (OSTI)

The nearby low-luminosity active galactic nucleus (LLAGN) NGC 4258 has a weak radio continuum component at the galactic center. We investigate its radio spectral properties on the basis of our new observations using the Nobeyama Millimeter Array at 100 GHz and archival data from the Very Large Array at 1.7-43 GHz and the James Clerk Maxwell telescope at 347 GHz. The NGC 4258 nuclear component exhibits (1) an intra-month variable and complicated spectral feature at 5-22 GHz and (2) a slightly inverted spectrum at 5-100 GHz ({alpha} {approx} 0.3; F {sub {nu}}{proportional_to}{nu}{sup {alpha}}) in time-averaged flux densities, which are also apparent in the closest LLAGN M81. These similarities between NGC 4258 and M81 in radio spectral natures in addition to previously known core shift in their AU-scale jet structures produce evidence that the same mechanism drives their nuclei. We interpret the observed spectral property as the superposition of emission spectra originating at different locations with frequency-dependent opacity along the nuclear jet. Quantitative differences between NGC 4258 and M81 in terms of jet/counter jet ratio, radio loudness, and degree of core shift can be consistently understood by fairly relativistic speeds ({Gamma} {approx}> 3) of jets and their quite different inclinations. The picture established from the two closest LLAGNs is useful for understanding the physical origin of unresolved and flat/inverted spectrum radio cores that are prevalently found in LLAGNs, including Sgr A*, with starved supermassive black holes in the present-day universe.

Doi, Akihiro [The Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuou-ku, Sagamihara, Kanagawa 252-5210 (Japan)] [The Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuou-ku, Sagamihara, Kanagawa 252-5210 (Japan); Kohno, Kotaro [Institute of Astronomy, The University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan)] [Institute of Astronomy, The University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan); Nakanishi, Kouichiro [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)] [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Kameno, Seiji [Department of Physics, Faculty of Science, Kagoshima University, 1-21-35 Korimoto, Kagoshima, Kagoshima 890-0065 (Japan)] [Department of Physics, Faculty of Science, Kagoshima University, 1-21-35 Korimoto, Kagoshima, Kagoshima 890-0065 (Japan); Inoue, Makoto [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China)] [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China); Hada, Kazuhiro [INAF, Istituto di Radioastronomia, via Gobetti 101, Bologna I-40129 (Italy)] [INAF, Istituto di Radioastronomia, via Gobetti 101, Bologna I-40129 (Italy); Sorai, Kazuo [Department of Physics, Graduate School of Science, Hokkaido University, Kita 10 Nishi 8, Sapporo 060-0810 (Japan)] [Department of Physics, Graduate School of Science, Hokkaido University, Kita 10 Nishi 8, Sapporo 060-0810 (Japan)

2013-03-01T23:59:59.000Z

428

Through-the-earth radio  

DOE Patents [OSTI]

A method and apparatus for effective through-the-earth communication involves a signal input device connected to a transmitter operating at a predetermined frequency sufficiently low to effectively penetrate useful distances through-the earth, and having an analog to digital converter receiving the signal input and passing the signal input to a data compression circuit that is connected to an encoding processor, the encoding processor output being provided to a digital to analog converter. An amplifier receives the analog output from the digital to analog converter for amplifying said analog output and outputting said analog output to an antenna. A receiver having an antenna receives the analog output passes the analog signal to a band pass filter whose output is connected to an analog to digital converter that provides a digital signal to a decoding processor whose output is connected to an data decompressor, the data decompressor providing a decompressed digital signal to a digital to analog converter. An audio output device receives the analog output form the digital to analog converter for producing audible output.

Reagor, David (Los Alamos, NM); Vasquez-Dominguez, Jose (Los Alamos, NM)

2006-05-09T23:59:59.000Z

429

National Radio Astronomy Observatory Electronics Division Technical Note No. 219  

E-Print Network [OSTI]

1 National Radio Astronomy Observatory Electronics Division Technical Note No. 219 Measurements of Automotive Radar Emissions received by a Radio Astronomy Observatory Darrel Emerson (National Radio Astronomy (Continental Corporation, A.D.C. Automotive Distance Control Systems GmbH, Germany), Juergen

Groppi, Christopher

430

Network Cooperation for Energy Saving in Green Radio Communications  

E-Print Network [OSTI]

1 Network Cooperation for Energy Saving in Green Radio Communications Muhammad Ismail and Weihua investigate network cooperation as a means of energy saving in green radio communications. The objective in the following. RENEWABLE ENERGY SOURCES From an environmental perspective, the objective of green radio

Zhuang, Weihua

431

Energy Efficient Transmissions in MIMO Cognitive Radio Networks  

E-Print Network [OSTI]

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

Huang, Jianwei

432

1 Spectrum Sharing Games of Network Operators and Cognitive Radios  

E-Print Network [OSTI]

Contents 1 Spectrum Sharing Games of Network Operators and Cognitive Radios Mohammad Hossein advances in radio technology, the spectrum regulators have opened some parts of the available spectrum operators and cognitive radios. Because of the dynamic nature of spectrum sharing, it is difficult

Bencsáth, Boldizsár

433

THE COMPACT STEEP SPECTRUM AND GHZ PEAKED SPECTRUM RADIO SOURCES  

E-Print Network [OSTI]

THE COMPACT STEEP SPECTRUM AND GHZ PEAKED SPECTRUM RADIO SOURCES Christopher P. O'Dea Space@stsci.edu ABSTRACT I review the radio to X­ray properties of GHz Peaked Spectrum (GPS) and Compact Steep Spectrum The GHz Peaked Spectrum (GPS) and Compact Steep Spectrum (CSS) radio sources make up significant fractions

434

Sequential Detection based Cooperative Spectrum Sensing Algorithms in Cognitive Radio  

E-Print Network [OSTI]

Sequential Detection based Cooperative Spectrum Sensing Algorithms in Cognitive Radio Arun considers the problem of Spectrum Sensing in Cognitive Radio Networks. For this we use a recently developed is not experienced by our algorithm. Keywords-Cognitive Radio, Cooperative Spectrum Sensing, Decentralized Sequential

Sharma, Vinod

435

Competitive Interference-aware Spectrum Access in Cognitive Radio Networks  

E-Print Network [OSTI]

Competitive Interference-aware Spectrum Access in Cognitive Radio Networks Jocelyne Elias, Fabio studies the spectrum access problem in cognitive radio networks from a game theoretical perspective. Finally, we provide numerical results of the proposed spectrum access game in several cognitive radio

Boyer, Edmond

436

High Throughput Spectrum-aware Routing for Cognitive Radio Networks  

E-Print Network [OSTI]

High Throughput Spectrum-aware Routing for Cognitive Radio Networks Ashwin Sampath, Lei Yang, Lili, wireless nodes equipped with cognitive radios [11] do not operate on statically as- signed spectrum who own the spectrum, e.g. analog TV broadcast stations. Such flexibility means cognitive radios can

Zhao, Ben Y.

437

Censored Truncated Sequential Spectrum Sensing for Cognitive Radio Networks  

E-Print Network [OSTI]

1 Censored Truncated Sequential Spectrum Sensing for Cognitive Radio Networks Sina Maleki Geert Leus Abstract Reliable spectrum sensing is a key functionality of a cognitive radio network. Cooperative spectrum sensing improves the detection reliability of a cognitive radio system but also increases

Leus, Geert

438

Robust Performance of Spectrum Sensing in Cognitive Radio Networks  

E-Print Network [OSTI]

1 Robust Performance of Spectrum Sensing in Cognitive Radio Networks Shimin Gong, Ping Wang) in cognitive radio networks requires SUs to be spectrum aware and know which spectrum bands are occupied by PUs and reduces the system sensitivity on decision variables. Index Terms Cognitive radio network, spectrum

Huang, Jianwei

439

: Correlation-Based Cooperative Spectrum Sensing in Cognitive Radio Networks  

E-Print Network [OSTI]

(CORN)2 : Correlation-Based Cooperative Spectrum Sensing in Cognitive Radio Networks Dongyue Xue is referred to as cognitive radio networks (CRNs) [2]. Based on the ambient spectrum information, cognitive for cognitive radio networks to minimize energy consumption. A sensing quality metric is defined as a measure

Paris-Sud XI, Université de

440

Reputation Aware Collaborative Spectrum Sensing for Mobile Cognitive Radio Networks  

E-Print Network [OSTI]

Reputation Aware Collaborative Spectrum Sensing for Mobile Cognitive Radio Networks Abstract ­ The task of spectrum sensing for Dynamic Spectrum Access in Cognitive Radio Networks (CRNs) is very of Cognitive Radio (CR) operation is the opportunistic utilization of licensed spectrum bands by the Secondary

Zou, Cliff C.

Note: This page contains sample records for the topic "radio frequency identification" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Binary Consensus for Cooperative Spectrum Sensing in Cognitive Radio Networks  

E-Print Network [OSTI]

Binary Consensus for Cooperative Spectrum Sensing in Cognitive Radio Networks Shwan Ashrafi, Cooperative Spectrum Sensing. I. INTRODUCTION Cognitive Radio (CR), introduced by Mitola [1], is expected). As such, cognitive radio emerged as a possible solution by trying to use the spectrum holes and thus

Mostofi, Yasamin

442

Throughput Enhancing Cooperative Spectrum Sensing Strategies for Cognitive Radios  

E-Print Network [OSTI]

Throughput Enhancing Cooperative Spectrum Sensing Strategies for Cognitive Radios Kyounghwan Lee growth of wireless services continues to accelerate the exhaustion of usable radio spectrum. The radio channels licensed to the primary users. A main chal- lenge in this case is to design a spectrum sensing

Yener, Aylin

443

Robust Distributed Spectrum Sensing in Cognitive Radio Networks  

E-Print Network [OSTI]

unlicensed radios to operate in licensed spectrum, provided no harmful interference is expe- riencedRobust Distributed Spectrum Sensing in Cognitive Radio Networks Ruiliang Chen, Jung-Min Park {rlchen, jungmin, kgbian}@vt.edu Abstract--Distributed spectrum sensing (DSS) enables a Cog- nitive Radio

444

Pop Up Radio Archive: A Solution for Independent Producers  

E-Print Network [OSTI]

Pop Up Radio Archive: A Solution for Independent Producers Anne Wootton, Bailey Smith, and Christen Penny UC Berkeley School of Information May 4, 2012 #12;Pop Up Radio Archive 2 Abstract Independent" and "dream of a system where [retrieval is easier]" (Silva). Pop Up Radio Archive is a free, open

Militzer, Burkhard

445

DEEP 1.4 GHz FOLLOW-UP OF THE STEEP SPECTRUM RADIO HALO IN A521  

SciTech Connect (OSTI)

In a recent paper, we reported on the discovery of a radio halo with very steep spectrum in the merging galaxy cluster A521 through observations with the Giant Metrewave Radio Telescope. We showed that the steep spectrum of the halo is inconsistent with a secondary origin of the relativistic electrons and supports a turbulent acceleration scenario. At that time, due to the steep spectrum, the available observations at 1.4 GHz (archival NRAO-Very Large Array-VLA-CnB-configuration data) were not adequate to accurately determine the flux density associated with the radio halo. In this paper, we report the detection at 1.4 GHz of the radio halo in A521 using deep VLA observations in the D configuration. We use these new data to confirm the steep spectrum of the object. We consider A521 the prototype of a population of very steep spectrum halos. This population is predicted assuming that turbulence plays an important role in the acceleration of relativistic particles in galaxy clusters, and we expect it will be unveiled by future surveys at low frequencies with the LOFAR and LWA radio telescopes.

Dallacasa, D.; Macario, G.; Setti, G. [Dipartimento di Astronomia, Universita di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Brunetti, G.; Cassano, R.; Venturi, T. [INAF-Istituto di Radioastronomia, via Gobetti 101, I-40129 Bologna (Italy); Giacintucci, S. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Kassim, N. E.; Lane, W. [Naval Research Laboratory, Code 7213, Washington, DC 20375-5320 (United States)

2009-07-10T23:59:59.000Z

446

Chameleonic Radio Technical Memo No. 11  

E-Print Network [OSTI]

Chameleonic Radio Technical Memo No. 11 An Audio System for the Blackfin S.M. Shajedul Hasan and S Institute & State University Blacksburg, VA 24061 #12;An Audio System for the Blackfin S.M. Shajedul Hasan Institute & State University, Blacksburg VA 24061 USA. E-mail: hasan@vt.edu 1 #12;1 Introduction

Ellingson, Steven W.

447

Chameleonic Radio Technical Memo No. 15  

E-Print Network [OSTI]

Receiver based on USRP and OSSIE," S.M. Shajedul Hasan and P. Balister, December 14, 2005. [3] 2. "An Hasan and S.W. Ellingson, January 24, 2006. [4] 3. "Implementation Status of the SCA-Based FM Radio," P Interface," S.M. Shajedul Hasan and Kyehun Lee, July 23, 2006

Ellingson, Steven W.

448

Chameleonic Radio Technical Memo No. 23  

E-Print Network [OSTI]

Hasan, M. Harun, and C.R. Anderson October 5, 2007 Bradley Dept. of Electrical & Computer Engineering S.W. Ellingson , S.M. Shajedul Hasan, M. Harun, and C.R. Anderson October 7, 2007 Contents 1 Wideband RF Downconverter for the NIJ Public Safety Radio," S.M. Shajedul Hasan and S.W. Ellingson

Ellingson, Steven W.

449

NATIONAL RADIO ASTRONOMY OBSERVATORY CHARLOTTESVILLE) VA  

E-Print Network [OSTI]

NATIONAL RADIO ASTRONOMY OBSERVATORY CHARLOTTESVILLE) VA ELECTRONICS DIVISION INTERNAL REPORT No ' : : lg Measurement Programs DETECTO R1 . · · · · .· · · . · · · · · · · NOISEL3.B. . 9· · . · · · · · · · · . . . Automated ' : : lg Measurement Programs DETECTO R1

Groppi, Christopher

450

Molecular gas in nearby elliptical radio galaxies  

E-Print Network [OSTI]

Powerful radio-AGN are hosted by massive elliptical galaxies which are usually very poor in molecular gas. Nevertheless the central Black Hole (BH) needs molecular gas for the nuclear activity. Thus it is important to study the origin, the distribution and the kinematics of the molecular gas in such objects. We have performed at the IRAM-30m telescope a survey of the CO(1-0) and CO(2-1) emission in the most powerful radio galaxies of the Local Universe, selected only on the basis of their radio continuum fluxes. The main result of that survey is the low content in molecular gas of such galaxies compared to Seyfert galaxies. The median value of the molecular gas mass is 4x10^8 Msun. Moreover, the CO spectra indicate the presence of a central molecular gas disk in some of these radio galaxies. We complemented this survey with photometric data of SPITZER and IRAS fluxes with the purpose to study the dust and its relation with the molecular gas and AGN.

B. Ocana-Flaquer; S. Leon; J. Lim; F. Combes; Dinh-V-Trung

2008-03-31T23:59:59.000Z

451

Radio Astronomy Fundamentals II John Simonetti  

E-Print Network [OSTI]

source is hard to distinguish from the random thermal noise present in a receiver. Power measurements of speeds in a gas is a Rayleigh distribution). Finally, received power is proportional to the square standard deviation. The power when pointing at a radio source might just be a little stronger

Ellingson, Steven W.

452

Barrier Immune Radio Communications for Demand Response  

E-Print Network [OSTI]

LBNL-2294E Barrier Immune Radio Communications for Demand Response F. Rubinstein, G. Ghatikar, J Ann Piette of Lawrence Berkeley National Laboratory's (LBNL) Demand Response Research Center (DRRC and Environment's (CIEE) Demand Response Emerging Technologies Development (DRETD) Program, under Work for Others

453

Reliable Link Maintenance in Cognitive Radio Systems  

E-Print Network [OSTI]

resources and overcome the under-utilization of licensed spectrum. Since the licensed user still keeps) have to vacate the spectrum in case the licensed user claims it. In order to maintain the qualityReliable Link Maintenance in Cognitive Radio Systems Daniel Willkomm, James Gross and Adam Wolisz

Gross, James

454

High frequency reference electrode  

DOE Patents [OSTI]

A high frequency reference electrode for electrochemical experiments comprises a mercury-calomel or silver-silver chloride reference electrode with a layer of platinum around it and a layer of a chemically and electrically resistant material such as TEFLON around the platinum covering all but a small ring or halo' at the tip of the reference electrode, adjacent to the active portion of the reference electrode. The voltage output of the platinum layer, which serves as a redox electrode, and that of the reference electrode are coupled by a capacitor or a set of capacitors and the coupled output transmitted to a standard laboratory potentiostat. The platinum may be applied by thermal decomposition to the surface of the reference electrode. The electrode provides superior high-frequency response over conventional electrodes. 4 figs.

Kronberg, J.W.

1994-05-31T23:59:59.000Z

455

Frequency ratio method for seismic modeling of Gamma Doradus stars  

E-Print Network [OSTI]

A method for obtaining asteroseismological information of a Gamma Doradus oscillating star showing at least three pulsation frequencies is presented. This method is based on a first-order asymptotic g-mode expression, in agreement with the internal structure of Gamma Doradus stars. The information obtained is twofold: 1) a possible identification of the radial order n and degree l of observed frequencies (assuming that these have the same l), and 2) an estimate of the integral of the buoyancy frequency (Brunt-Vaisala) weighted over the stellar radius along the radiative zone. The accuracy of the method as well as its theoretical consistency are also discussed for a typical Gamma Doradus stellar model. Finally, the frequency ratios method has been tested with observed frequencies of the Gamma Doradus star HD 12901. The number of representative models verifying the complete set of constraints (the location in the HR diagram, the Brunt-Vaisala frequency integral, the observed metallicity and frequencies and a re...

Moya, A; Amado, P J; Martin-Ruiz, S; Garrido, R

2004-01-01T23:59:59.000Z

456

Simultaneous Radio to (Sub-) Mm-Monitoring of Variability and Spectral Shape Evolution of Potential GLAST Blazars  

SciTech Connect (OSTI)

The Large Area Telescope (LAT) instrument onboard GLAST offers a tremendous opportunity for future blazar studies. In order to fully benefit from its capabilities and to maximize the scientific return from the LAT, it is of great importance to conduct dedicated multi-frequency monitoring campaigns that will result comprehensive observations. Consequently, we initiated an effort to conduct a GLAST-dedicated, quasi-simultaneous, broad-band flux-density (and polarization) monitoring of potential GLAST blazars with the Effelsberg and OVRO radio telescopes (11 cm to 7mm wavelength). Here, we present a short overview of these activities which will complement the multi-wavelengths activities of the GLAST/LAT collaboration towards the 'low-energy' radio bands. Further we will give a brief outlook including the extension of this coordinated campaign towards higher frequencies and future scientific aims.

Fuhrmann, L.; Zensus, J.A.; Krichbaum, T.P.; Angelakis, E.; /Bonn, Max Planck Inst., Radioastron.; Readhead, A.C.S.; /Caltech

2011-11-29T23:59:59.000Z

457

Abstract--Reconfigurable Radio Systems (RRS), based on Software Defined Radio (SDR) and Mobile Ad-hoc Network  

E-Print Network [OSTI]

Abstract--Reconfigurable Radio Systems (RRS), based on Software Defined Radio (SDR) and Mobile Ad-hoc by the proposed scheme, while keeping the important false positive rate at a very low level. Keywords--Mobile ad-hoc (SDR), Mobile Ad-hoc Networks (MANETs) and Cognitive Radio (CR). Research on these technologies has

458

E-Print Network 3.0 - air cargo inspection Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Abstract This paper describes Cargo... sensor networks and radio- frequency identification (RFID). CargoNet was aimed at applications Source: Massachusetts Institute...

459

Marine asset security and tracking (MAST) system  

DOE Patents [OSTI]

Methods and apparatus are described for marine asset security and tracking (MAST). A method includes transmitting identification data, location data and environmental state sensor data from a radio frequency tag. An apparatus includes a radio frequency tag that transmits identification data, location data and environmental state sensor data. Another method includes transmitting identification data and location data from a radio frequency tag using hybrid spread-spectrum modulation. Another apparatus includes a radio frequency tag that transmits both identification data and location data using hybrid spread-spectrum modulation.

Hanson, Gregory Richard (Clinton, TN); Smith, Stephen Fulton (Loudon, TN); Moore, Michael Roy (Corryton, TN); Dobson, Eric Lesley (Charleston, SC); Blair, Jeffrey Scott (Charleston, SC); Duncan, Christopher Allen (Marietta, GA); Lenarduzzi, Roberto (Knoxville, TN)

2008-07-01T23:59:59.000Z

460

Verification of particle simulation of radio frequency waves in fusion Animesh Kuley,1,2,a)  

E-Print Network [OSTI]

, China 3 Tri Alpha Energy, Inc., Post Office Box 7010, Rancho Santa Margarita, California 92688, USA step in the quest for the fusion energy. First, the RF waves in ITER will be used to deliver sufficient

Lin, Zhihong

Note: This page contains sample records for the topic "radio frequency identification" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Ways to improve the efficiency and reliability of radio frequency driven negative ion sources for fusion  

SciTech Connect (OSTI)

Large RF driven negative hydrogen ion sources are being developed at IPP Garching for the future neutral beam injection system of ITER. The overall power efficiency of these sources is low, because for the RF power supply self-excited generators are utilized and the plasma is generated in small cylindrical sources (“drivers”) and expands into the source main volume. At IPP experiments to reduce the primary power and the RF power required for the plasma production are performed in two ways: The oscillator generator of the prototype source has been replaced by a transistorized RF transmitter and two alternative driver concepts, a spiral coil, in which the field is concentrated by ferrites, which omits the losses by plasma expansion and a helicon source are being tested.

Kraus, W., E-mail: kraus@ipp.mpg.de [Max-Planck-Institut für Plasmaphysik (IPP), Boltzmannstr. 2, 85748 Garching (Germany); Briefi, S.; Fantz, U. [Max-Planck-Institut für Plasmaphysik (IPP), Boltzmannstr. 2, 85748 Garching (Germany) [Max-Planck-Institut für Plasmaphysik (IPP), Boltzmannstr. 2, 85748 Garching (Germany); AG Experimentelle Plasmaphysik, Universität Augsburg, 86135 Augsburg (Germany); Gutmann, P.; Doerfler, J. [AG Experimentelle Plasmaphysik, Universität Augsburg, 86135 Augsburg (Germany)] [AG Experimentelle Plasmaphysik, Universität Augsburg, 86135 Augsburg (Germany)

2014-02-15T23:59:59.000Z

462

Radio-frequency and microwave load comprising a carbon-bonded carbon fiber composite  

DOE Patents [OSTI]

A billet of low-density carbon-bonded carbon fiber (CBCF) composite is machined into a desired attenuator or load element shape (usually tapering). The CBCF composite is used as a free-standing load element or, preferably, brazed to the copper, brass or aluminum components of coaxial transmission lines or microwave waveguides. A novel braze method was developed for the brazing step. The resulting attenuator and/or load devices are robust, relatively inexpensive, more easily fabricated, and have improved performance over conventional graded-coating loads. 9 figs.

Lauf, R.J.; McMillan, A.D.; Johnson, A.C.; Everleigh, C.A.; Moorhead, A.J.

1998-04-21T23:59:59.000Z

463

Enhanced Field Emission Studies on Niobium Surfaces Relevant to High Field Superconducting Radio-Frequency Devices  

SciTech Connect (OSTI)

Enhanced field emission (EFE) presents the main impediment to higher acceleration gradients in superconducting niobium (Nb) radiofrequency cavities for particle accelerators. The strength, number and sources of EFE sites strongly depend on surface preparation and handling. The main objective of this thesis project is to systematically investigate the sources of EFE from Nb, to evaluate the best available surface preparation techniques with respect to resulting field emission, and to establish an optimized process to minimize or eliminate EFE. To achieve these goals, a scanning field emission microscope (SFEM) was designed and built as an extension to an existing commercial scanning electron microscope (SEM). In the SFEM chamber of ultra high vacuum, a sample is moved laterally in a raster pattern under a high voltage anode tip for EFE detection and localization. The sample is then transferred under vacuum to the SEM chamber equipped with an energy-dispersive x-ray spectrometer for individual emitting site characterization. Compared to other systems built for similar purposes, this apparatus has low cost and maintenance, high operational flexibility, considerably bigger scan area, as well as reliable performance. EFE sources from planar Nb have been studied after various surface preparation, including chemical etching and electropolishing, combined with ultrasonic or high-pressure water rinse. Emitters have been identified, analyzed and the preparation process has been examined and improved based on EFE results. As a result, field-emission-free or near field-emission-free surfaces at ~140 MV/m have been consistently achieved with the above techniques. Characterization on the remaining emitters leads to the conclusion that no evidence of intrinsic emitters, i.e., no fundamental electric field limit induced by EFE, has been observed up to ~140 MV/m. Chemically etched and electropolished Nb are compared and no significant difference is observed up to ~140 MV/m. To address concerns on the effect of natural air drying process on EFE, a comparative study was conducted on Nb and the results showed insignificant difference under the experimental conditions. Nb thin films deposited on Cu present a possible alternative to bulk Nb in superconducting cavities. The EFE performance of a preliminary energetically deposited Nb thin film sample are presented.

Tong Wang

2002-09-18T23:59:59.000Z

464

Preliminary Concept for the Project X CW Radio Frequency Quadrupole (RFQ)  

E-Print Network [OSTI]

be backed up by a canted coil spring, which will absorb anyBehind the step, an R F coil spring on the tuner O D will

Virostek, S. P.

2013-01-01T23:59:59.000Z

465

arXiv:astro-ph/0309647v123Sep2003 Hydra A at Low Radio Frequencies  

E-Print Network [OSTI]

Faraday rota- tion measure (RM) and asymmetry in both the RM and depolarization between the kpc-scale jets suggest an inclination angle of 48 (Taylor & Per- ley 1993), with the northern jet lying closer to us

Taylor, Greg

466

Development of an international standard for electromagnetic interference (EMI)/radio frequency interference (RFI)  

SciTech Connect (OSTI)

This paper covers the development of an international standard that establishes the requirements for electromagnetic compatibility testing of instrumentation and control equipment supplied for use in systems important to safety at nuclear power plants. The standard lists the applicable IEC standards (principally the IEC 61000 series) which define the general test methods, and provides the necessary application-specific parameters and criteria to ensure that nuclear safety requirements are met. This standard was prepared with the leadership by the Russian National Committee representatives to the International Electrotechnical Commission (IEC). (authors)

Sarylov, V. [EMC Test Center, NUIT, FSUE RIPT, Moscow (Russian Federation); Shumov, S. [FSUE SEC SNIIP, Moscow (Russian Federation); Quinn, E. [ANS, Dana Point, CA (United States)

2006-07-01T23:59:59.000Z

467

Focused excimer laser initiated, radio frequency sustained high pressure air plasmas  

E-Print Network [OSTI]

Research Building, 1500 Engineering Drive, Madison, Wisconsin 53706, USA (Received 5 August 2011; accepted, and vibrational neutral temperatures and the associated neutral gas temperature. From this and the associated such as defense, manufacturing, energy, and medicine. Specific applications include materials processing

Scharer, John E.

468

Radio-frequency and microwave load comprising a carbon-bonded carbon fiber composite  

DOE Patents [OSTI]

A billet of low-density carbon-bonded carbon fiber (CBCF) composite is machined into a desired attenuator or load element shape (usually tapering). The CBCF composite is used as a free-standing load element or, preferably, brazed to the copper, brass or aluminum components of coaxial transmission lines or microwave waveguides. A novel braze method was developed for the brazing step. The resulting attenuator and/or load devices are robust, relatively inexpensive, more easily fabricated, and have improved performance over conventional graded-coating loads.

Lauf, Robert J. (Oak Ridge, TN); McMillan, April D. (Knoxville, TN); Johnson, Arvid C. (Lake in the Hills, IL); Everleigh, Carl A. (Raleigh, NC); Moorhead, Arthur J. (Knoxville, TN)

1998-01-01T23:59:59.000Z

469

Porcelain-coated antenna for radio-frequency driven plasma source  

DOE Patents [OSTI]

A new porcelain-enamel coated antenna creates a clean plasma for volume or surface-conversion ion sources. The porcelain-enamel coating is hard, electrically insulating, long lasting, non fragile, and resistant to puncture by high energy ions in the plasma. Plasma and ion production using the porcelain enamel coated antenna is uncontaminated with filament or extraneous metal ions because the porcelain does not evaporate and is not sputtered into the plasma during operation. Ion beams produced using the new porcelain-enamel coated antenna are useful in ion implantation, high energy accelerators, negative, positive, or neutral beam applications, fusion, and treatment of chemical or radioactive waste for disposal. For ion implantation, the appropriate species ion beam generated with the inventive antenna will penetrate large or small, irregularly shaped conducting objects with a narrow implantation profile. 8 figs.

Leung, K.N.; Wells, R.P.; Craven, G.E.

1996-12-24T23:59:59.000Z

470

Radio-frequency powered glow discharge device and method with high voltage interface  

DOE Patents [OSTI]

A high voltage accelerating potential, which is supplied by a high voltage direct current power supply, is applied to the electrically conducting interior wall of an RF powered glow discharge cell. The RF power supply desirably is electrically grounded, and the conductor carrying the RF power to the sample held by the probe is desirably shielded completely excepting only the conductor's terminal point of contact with the sample. The high voltage DC accelerating potential is not supplied to the sample. A high voltage capacitance is electrically connected in series between the sample on the one hand and the RF power supply and an impedance matching network on the other hand. The high voltage capacitance isolates the high DC voltage from the RF electronics, while the RF potential is passed across the high voltage capacitance to the plasma. An inductor protects at least the RF power supply, and desirably the impedance matching network as well, from a short that might occur across the high voltage capacitance. The discharge cell and the probe which holds the sample are configured and disposed to prevent the probe's components, which are maintained at ground potential, from bridging between the relatively low vacuum region in communication with the glow discharge maintained within the cell on the one hand, and the relatively high vacuum region surrounding the probe and cell on the other hand. The probe and cell also are configured and disposed to prevent the probe's components from electrically shorting the cell's components.

Duckworth, Douglas C. (Knoxville, TN); Marcus, R. Kenneth (Clemson, SC); Donohue, David L. (Vienna, AT); Lewis, Trousdale A. (Oak Ridge, TN)

1994-01-01T23:59:59.000Z

471

Radio-frequency powered glow discharge device and method with high voltage interface  

DOE Patents [OSTI]

A high voltage accelerating potential, which is supplied by a high voltage direct current power supply, is applied to the electrically conducting interior wall of an RF powered glow discharge cell. The RF power supply desirably is electrically grounded, and the conductor carrying the RF power to the sample held by the probe is desirably shielded completely excepting only the conductor's terminal point of contact with the sample. The high voltage DC accelerating potential is not supplied to the sample. A high voltage capacitance is electrically connected in series between the sample on the one hand and the RF power supply and an impedance matching network on the other hand. The high voltage capacitance isolates the high DC voltage from the RF electronics, while the RF potential is passed across the high voltage capacitance to the plasma. An inductor protects at least the RF power supply, and desirably the impedance matching network as well, from a short that might occur across the high voltage capacitance. The discharge cell and the probe which holds the sample are configured and disposed to prevent the probe's components, which are maintained at ground potential, from bridging between the relatively low vacuum region in communication with the glow discharge maintained within the cell on the one hand, and the relatively high vacuum region surrounding the probe and cell on the other hand. The probe and cell also are configured and disposed to prevent the probe's components from electrically shorting the cell's components. 11 figures.

Duckworth, D.C.; Marcus, R.K.; Donohue, D.L.; Lewis, T.A.

1994-06-28T23:59:59.000Z

472

Structural properties of dusty plasma in direct current and radio frequency gas discharges  

SciTech Connect (OSTI)

This paper presents radial distribution functions of dust particles obtained experimentally in dc and rf discharges. Pressure and interaction energy of dusty particles were calculated on the basis of these functions. The Langevin dynamics computer simulation for each experiment was performed. The comparisons with computer simulations are made.

Ramazanov, T. S.; Dzhumagulova, K. N.; Jumabekov, A. N.; Dosbolayev, M. K. [Al Farabi Kazakh National University, IETP, Tole bi 96a, Almaty, 050012 (Kazakhstan)

2008-05-15T23:59:59.000Z

473

Current Sheet Formation in a Conical Theta Pinch Faraday Accelerator with Radio-frequency Assisted  

E-Print Network [OSTI]

). Pulsed inductive thrusters1 are one type of electrode-less plasma propulsion devices. Their operation plasma resistivity due to increasing pressure. Nomenclature d = distance from the cone inlet ne Electrode-less spacecraft propulsion thrusters are attractive devices due to their avoidance of lifetime

Choueiri, Edgar

474

Current Sheet Formation in a Conical Theta Pinch Faraday Accelerator with Radio-frequency Assisted  

E-Print Network [OSTI]

of a preionized plasma has been previously shown to allow for current sheet formation at lower discharge voltages, NJ 08544, Student Member AIAA. Chief Scientist of the Electric Propulsion and Plasma Dynamics Lab of electrodeless thrusters under development for use in space propulsion applications. Electrodeless thrusters

Choueiri, Edgar

475

Faraday Acceleration with Radio-frequency Assisted Discharge (FARAD) Edgar Y. Choueiri  

E-Print Network [OSTI]

. Polzin Electric Propulsion and Plasma Dynamics Laboratory (EPPDyL) Mechanical and Aerospace Engineering electrodeless accelerator concept that relies on an RF-assisted discharge, an applied magnetic field efficient plasma production, magnetic field guided mass injection, and electromagnetic acceleration

Choueiri, Edgar

476

Faraday Acceleration with Radio-frequency Assisted Discharge Edgar Y. Choueiri and Kurt A. Polzin  

E-Print Network [OSTI]

Electric Propulsion and Plasma Dynamics Laboratory (EPPDyL) Princeton University, Mechanical and Aerospace Abstract A new electrodeless accelerator concept that relies on an RF-assisted discharge, an applied of a preionized plasma allows for current sheet formation at lower discharge voltages and energies than those

Choueiri, Edgar

477

Single Stage Faraday Accelerator with Radio-frequency Assisted Discharge (SS-FARAD)  

E-Print Network [OSTI]

-assisted, pulsed, electrodeless accelerator concept that utilizes a single antenna coil for plasma generation be sufficiently isolated from the RF source without significant adverse affects on plasma generation. Nomenclature Pulsed inductive plasma accelerators are seen as a way to overcome major obstacles in other electric

Choueiri, Edgar

478

Porcelain-coated antenna for radio-frequency driven plasma source  

DOE Patents [OSTI]

A new porcelain-enamel coated antenna creates a clean plasma for volume or surface-conversion ion sources. The porcelain-enamel coating is hard, electrically insulating, long lasting, non fragile, and resistant to puncture by high energy ions in the plasma. Plasma and ion production using the porcelain enamel coated antenna is uncontaminated with filament or extraneous metal ion because the porcelain does not evaporate and is not sputtered into the plasma during operation. Ion beams produced using the new porcelain-enamel coated antenna are useful in ion implantation, high energy accelerators, negative, positive, or neutral beam applications, fusion, and treatment of chemical or radioactive waste for disposal. For ion implantation, the appropriate species ion beam generated with the inventive antenna will penetrate large or small, irregularly shaped conducting objects with a narrow implantation profile.

Leung, Ka-Ngo (Hercules, CA); Wells, Russell P. (Kensington, CA); Craven, Glen E. (Fremont, CA)

1996-01-01T23:59:59.000Z

479

Efficient Joint Detection Techniques in the Frequency Domain for Third Generation Mobile Radio Systems  

E-Print Network [OSTI]

Systems Marius Vollmer1,2 , J¨urgen G¨otze1 , Martin Haardt2 1. Dept. of Electrical Engineering 2. Siemens@dt.e-technik.uni-dortmund.de Martin.Haardt@icn.siemens.de mvo@dt.e-technik.uni-dortmund.de Marius.Vollmer@icn.siemens.de Abstract-circulant matrix. It is then possible to block- diagonalize the matrix by Fast Fourier Transforms. In addi- tion

Götze, Jürgen