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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

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

2

Radio frequency identification enabled wireless sensing for intelligent food logistics  

Science Journals Connector (OSTI)

...Hoekstra, Bastien Chopard and Peter Coveney Radio frequency identification enabled wireless sensing for intelligent food logistics Zhuo Zou Qiang Chen Ismail Uysal Lirong Zheng Phil. Trans. R. Soc. A 372, 20130313 (13 June 2014; Published online...

2014-01-01T23:59:59.000Z

3

An intelligent approach to handle False-Positive Radio Frequency Identification Anomalies  

Science Journals Connector (OSTI)

Radio Frequency Identification RFID technology allows wireless interaction between tagged objects and readers to automatically identify large groups of items. This technology is widely accepted in a number of application domains, however, it suffers ... Keywords: Bayesian Network, False-Positive Anomaly, Neural Network, Non-Monotonic Reasoning, Radio Frequency Identification --Rfid

Peter Darcy; Bela Stantic; Abdul Sattar

2011-11-01T23:59:59.000Z

4

Enhancement of electromagnetic propagation through complex media for Radio Frequency Identification  

E-Print Network [OSTI]

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

Marti, Uttara P

2005-01-01T23:59:59.000Z

5

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

6

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

7

Radio frequency identification enabled wireless sensing for intelligent food logistics  

Science Journals Connector (OSTI)

...semi-passive ultrahigh frequency (UHF) RFID...functionalities, energy source, processing and storage capabilities...backscattering in high frequency (HF) or UHF...changes as a response to the varying...low-cost and energy-efficient under...

2014-01-01T23:59:59.000Z

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 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

10

In-Born Radio Frequency Identification Devices for Safeguards Use at Gas-Centrifuge Enrichment Plants  

SciTech Connect (OSTI)

Global expansion of nuclear power has made the need for improved safeguards measures at Gas Centrifuge Enrichment Plants (GCEPs) imperative. One technology under consideration for safeguards applications is Radio Frequency Identification Devices (RFIDs). RFIDs have the potential to increase IAEA inspector"s efficiency and effectiveness either by reducing the number of inspection visits necessary or by reducing inspection effort at those visits. This study assesses the use of RFIDs as an integral component of the "Option 4" safeguards approach developed by Bruce Moran, U.S. Nuclear Regulatory Commission (NRC), for a model GCEP [1]. A previous analysis of RFIDs was conducted by Jae Jo, Brookhaven National Laboratory (BNL), which evaluated the effectiveness of an RFID tag applied by the facility operator [2]. This paper presents a similar evaluation carried out in the framework of Jo’s paper, but it is predicated on the assumption that the RFID tag is applied by the manufacturer at the birth of the cylinder, rather than by the operator. Relevant diversion scenarios are examined to determine if RFIDs increase the effectiveness and/ or efficiency of safeguards in these scenarios. Conclusions on the benefits offered to inspectors by using in-born RFID tagging are presented.

Ward,R.; Rosenthal,M.

2009-07-12T23:59:59.000Z

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

Frequencies for Radio Astronomy  

Science Journals Connector (OSTI)

... must therefore be achieved through the combined action of three international scientific unions, IAU (astronomy), COSPAR (space) and URSI (radio), which jointly delegate members to an ... jointly delegate members to an Inter-Union Commission for the Allocation of Frequencies for Radio Astronomy and Space Science (IUCAF). This Commission discusses the scientific case for protecting various ...

F. G. SMITH

1970-10-31T23:59:59.000Z

13

Identification of Minority Ion-Cyclotron Emission during Radio Frequency Heating in the JET Tokamak  

Science Journals Connector (OSTI)

First measurements and identification of minority ion-cyclotron emission (MICE) during ICRF (H)D minority heating in the JET tokamak are presented. An inner wall radiofrequency (rf) probe shows the new single MICE spectral line, down-shifted from the heating frequency and appearing ?400 ms after the ICRH switch-on. The line is narrow (??/??0.04), characterized by the ion-cyclotron frequency of minority protons in the outer-edge midplane plasma and is observed irrespective of whether single or multifrequency ICRH is applied. The observations are consistent with the classical evolution and population of the plasma edge with ?3 MeV ICRH protons on orbits near the outboard limiters. Particle loss and energy filtering contribute to a local non-Maxwellian energetic ion distribution, which is susceptible to ion-cyclotron instability.

G. A. Cottrell

2000-03-13T23:59:59.000Z

14

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

15

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 ...

16

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.

17

METHODS OF RADIO-FREQUENCY CURRENT DRIVE  

E-Print Network [OSTI]

METHODS OF RADIO-FREQUENCY CURRENT DRIVE N. J. FISCH* Princeton Plasma Physics Laboratory-670 Radio-frequency waves can penetrate thermonuclear plasmas, depositing momentum and energy with great. INTRODUCTION Using radio-frequency (rf) waves to drive the toroidal current in tokamak reactors is attractive

18

Photonic Radio-Frequency Phase Detector based on Radio-Frequency to Intermediate-Frequency Phase Mapping  

Science Journals Connector (OSTI)

A photonic radio-frequency phase detector based on radio-frequency (RF) to intermediate-frequency mapping is demonstrated, and the theoretical principle of the design is explained.

Sun, Dongning; Dong, Yi; Wang, Siwei; Xia, Zongyang; Xie, Weilin; Shi, Hongxiao; Yi, Lilin; Hu, Weisheng

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

LOFAR, a new low frequency radio telescope  

E-Print Network [OSTI]

LOFAR, the Low Frequency Array, is a large radio telescope consisting of approximately 100 soccer-field sized antenna stations spread over a region of 400 km in diameter. It will operate at frequencies from ~10 to 240 MHz, with a resolution at 240 MHz of better than an arcsecond. Its superb sensitivity will allow for studies of a broad range of astrophysical topics, including reionisation, transient radio sources and cosmic rays, distant galaxies and AGNs. In this contribution a status rapport of the LOFAR project and an overview of the science case is presented.

H. J. A. Rottgering

2003-09-19T23:59:59.000Z

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.


21

Burst Radio-Frequency Excited Pulsed Hollow-Cathode Lamp  

Science Journals Connector (OSTI)

Transient emission characteristics of a hollow-cathode lamp driven by a pulsed current in combination with a radio-frequency burst signal are described. The radio-frequency field...

Araki, Tsutomu; Walters, John P; Minami, Shigeo

1980-01-01T23:59:59.000Z

22

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

23

SOME UNSOLVED CHALLENGES IN RADIO-FREQUENCY HEATING AND  

E-Print Network [OSTI]

SOME UNSOLVED CHALLENGES IN RADIO-FREQUENCY HEATING AND CURRENT DRIVE N. J. FISCH* Princeton Plasma in the electronic version. I. INTRODUCTION There are many methods by which radio-frequency (rf) waves drive, 2013 doi:10.13182/FST13-682 Several unsolved challenges in radio-frequency heating and current drive

24

Rotating-radio-frequency ion traps T. Hasegawa*  

E-Print Network [OSTI]

rf ion trap, the rotating-radio-frequency rotating-rf trap, in which the motion of a charged particleRotating-radio-frequency ion traps T. Hasegawa* Department of Physics, Keio University, Kanagawa and Technology, Boulder, Colorado 80305, USA Received 9 July 2005; published 20 October 2005 We discuss a radio-frequency

25

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

26

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.

27

2010 Raj JainCSE574sWashington University in St. Louis Radio FrequencyRadio Frequency  

E-Print Network [OSTI]

. Louis RFID ReadersRFID Readers Sends a pulse of radio energy and listens for tags response Readers may24-1 ©2010 Raj JainCSE574sWashington University in St. Louis Radio FrequencyRadio Frequency;24-3 ©2010 Raj JainCSE574sWashington University in St. Louis What is RFID?What is RFID? Radio Frequency

Jain, Raj

28

Radio frequency ion source operated with field effect transistor based radio frequency system  

SciTech Connect (OSTI)

Characteristics of radio frequency (RF) plasma production are investigated using a field effect transistor inverter power supply as an RF wave source. With the frequency of around 0.3 MHz, an electron density over 10{sup 18} m{sup -3} is produced in argon plasma. Although lower densities are obtained in hydrogen plasma, it drastically increased up to 5x10{sup 18} m{sup -3} with an axial magnetic field of around 100 G applied in the driver region. Effects of the magnetic field and gas pressure are investigated in the RF produced plasma with the frequency of several hundred kilohertz.

Ando, A.; Komuro, A.; Matsuno, T. [Department of Electrical Engineering, Tohoku University, Sendai 980-8759 (Japan); Tsumori, K.; Takeiri, Y. [National Institute for Fusion Science, Toki 509-5292 (Japan)

2010-02-15T23:59:59.000Z

29

The Gaseous Electronics Conference radio-frequency reference cell: A defined parallel-plate radio-frequency system for experimental  

E-Print Network [OSTI]

The Gaseous Electronics Conference radio-frequency reference cell: A defined parallel-plate radio-frequency publication 3 September1993) A "referencecell" for generatingradio-frequency(rf) glow dischargesin gasesat a frequencyof 13.56MHz is described.The referencecell provides an experimental platform for comparing plasma

Kushner, Mark

30

E-Print Network 3.0 - assessing radio-isotope identification...  

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

radio-isotope identification Search Powered by Explorit Topic List Advanced Search Sample search results for: assessing radio-isotope identification Page: << < 1 2 3 4 5 > >> 1...

31

2006 Raj JainCSE574sWashington University in St. Louis Radio FrequencyRadio Frequency  

E-Print Network [OSTI]

18-1 ©2006 Raj JainCSE574sWashington University in St. Louis Radio FrequencyRadio Frequency;18-3 ©2006 Raj JainCSE574sWashington University in St. Louis What is RFID?What is RFID? ! Radio Frequency #. 96-bit block of read- only storage (ROM). " Read-write memory. " Tags may have embedded sensors (tire

Jain, Raj

32

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

33

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

34

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

35

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

36

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

37

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

38

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

39

New design of a radio-frequency plasma torch  

Science Journals Connector (OSTI)

A numerical model has been developed for predicting the two-dimensional flow and temperature fields in a radio-frequency (rf) plasma torch. The method employed here is based ... rates without interfering with the...

Toyonobu Yoshida; Kunihiko Nakagawa…

1981-03-01T23:59:59.000Z

40

Radio-frequency-excited carbon dioxide metal waveguide laser  

Science Journals Connector (OSTI)

A new type of waveguide laser is described in which a single-surface concave metal waveguide also doubles as the grounded electrode in a radio-frequency-excited gaseous discharge. The...

Grossman, Jonathan G; Casperson, Lee W; Stafsudd, Oscar M

1983-01-01T23:59:59.000Z

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.


41

Radio frequency overview of the high explosive radio telemetry project  

SciTech Connect (OSTI)

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

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

1998-12-31T23:59:59.000Z

42

Dual radio frequency plasma source: Understanding via electrical asymmetry effect  

SciTech Connect (OSTI)

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

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

2013-04-21T23:59:59.000Z

43

Method and Apparatus for Pasteurizing Shell Eggs Using Radio Frequency  

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

Method and Apparatus for Pasteurizing Shell Eggs Using Radio Frequency Method and Apparatus for Pasteurizing Shell Eggs Using Radio Frequency Heating" Inventors..--.. Christopher D. Brunkhorst, David J. Geveke, Andrew B. W. Bigley. This disclosure is directed to a system for pasteurizing shell eggs. The system includes an egg rotating assembly structured to rotate the egg, and electrodes that are in contact with the egg. The system is structured so that, as the rotating assembly rotates the egg, radio frequency energy is directed to the egg to pasteurize it. Nearly 200 million "shell eggs" are consumed in the United States (US) each day. "Shell eggs" are non-powdered conventional eggs that are naturally produced by hens. Shell eggs are among the most nutritious foods on earth and can be part of a healthy diet. However, some unbroken, clean, fresh

44

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

45

Plasma Paramagnetism in Radio-Frequency Fields  

Science Journals Connector (OSTI)

A study by experiment, simulation, and theory has found that a plasma responds paramagnetically to the external rf magnetic field applied perpendicular to the static magnetic field with frequency ?frequency. This effect can be exploited in the rf plugging and heating of plasmas; it explains the earlier rf plugging experiment (type-3 coil) of Watari et al. at Nagoya and possibly the rf heating experiment of Dikii et al. on the Uragan stellarator.

Y. Ohsawa; M. Inutake; T. Tajima; T. Hatori; T. Kamimura

1979-10-22T23:59:59.000Z

46

The characteristics of atmospheric radio frequency discharges with frequency increasing at a constant power density  

SciTech Connect (OSTI)

A computational model is used to investigate the characteristics of atmospheric radio frequency discharges by increasing frequency from 20 to 100 MHz at a constant power density. The simulation results show that increasing frequency can effectively enhance electron density before the transition frequency but after it the ignition is quenched then the electron density decreases. However this simulation also indicates the maximum time-averaged electron energy reduces monotonically with the excitation frequency increasing at a constant power density.

Zhang Yuantao; Li Qingquan; Lou Jie; Li Qingmin [School of Electrical Engineering, Shandong University, Jinan, Shandong Province 250061 (China)

2010-10-04T23:59:59.000Z

47

Emission of Radio-Frequency Waves from Plasmas  

Science Journals Connector (OSTI)

Observations of the radio-frequency emission from extraterrestrial plasmas and plasmas produced in the laboratory are described and various attempts at interpretation of the results are reviewed. Estimates are made of the probable loss of radiant energy from plasmas in proposed thermonuclear reactors.

G. Bekefi; Sanborn C. Brown

1961-01-01T23:59:59.000Z

48

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

49

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

E-Print Network [OSTI]

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

Kazakov, Georgy A

2014-01-01T23:59:59.000Z

50

Radio Frequency Diesel Particulate Filter Sensor Reduces Fuel Consumption, Wins R&D 100 Award  

Office of Energy Efficiency and Renewable Energy (EERE)

Radio Frequency Diesel Particulate Filter Sensor (RF-DPF) is a sensor that uses radio frequencies to measure the amount and distribution of soot and ash in the filters that remove particulate matter from the exhaust of diesel engines.

51

Temporally resolved ion velocity distribution measurements in a radio-frequency plasma sheath  

E-Print Network [OSTI]

and within a radio-frequency (RF) biased plasma sheath is studied experimentally with a pulsed laserTemporally resolved ion velocity distribution measurements in a radio-frequency plasma sheath B; therefore, radio-frequency (RF) biases which result in zero net electrical current to the substrate

California at Los Angles, University of

52

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

53

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

54

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

55

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

56

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

57

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

58

Heating mechanisms in radio-frequency-driven ultracold plasmas  

Science Journals Connector (OSTI)

Several mechanisms by which an external electromagnetic field influences the temperature of a plasma are studied analytically and specialized to the system of an ultracold plasma (UCP) driven by a uniform radio-frequency (rf) field. Heating through collisional absorption is reviewed and applied to UCPs. Furthermore, it is shown that the rf field modifies the three-body recombination process by ionizing electrons from intermediate high-lying Rydberg states and upshifting the continuum threshold, resulting in a suppression of three-body recombination. Heating through collisionless absorption associated with the finite plasma size is calculated in detail, revealing a temperature threshold below which collisionless absorption is ineffective.

P. W. Smorenburg; L. P. J. Kamp; O. J. Luiten

2012-06-20T23:59:59.000Z

59

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

60

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

E-Print Network [OSTI]

Two-Dimensional Numerical Modeling of Radio-Frequency Ion Engine Discharge Michael Meng-Tsuan Tsay-Frequency Ion Engine Discharge Michael Meng-Tsuan Tsay, Manuel Martinez-Sanchez August 2010 SSL # 14 Modeling of Radio-Frequency Ion Engine Discharge by Michael Meng-Tsuan Tsay Submitted to the Department

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.


61

Effect of radio frequency discharge power on dusty plasma parameters  

SciTech Connect (OSTI)

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

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

2009-08-01T23:59:59.000Z

62

Influence of excitation frequency on plasma parameters and etching characteristics of radio-frequency discharges  

Science Journals Connector (OSTI)

Abstract Plasma parameters such as electron density, electron-collision rate, resonance frequency and the bias voltage were shown to be important for the characterization of radio-frequency (RF) plasmas. By means of self-excited electron resonance spectroscopy (SEERS), the plasma parameters were compared at two different frequencies, 13.56 \\{MHz\\} and 40.68 MHz, in argon, oxygen, fluorine and their mixtures at low pressure. Upon increasing the generator frequency, more RF power has to be applied to achieve the same bias voltage. At the lower pressure, the bias voltage indicates the mean energy of the ions impacting on the substrate and causing damage at the surface. The experimental results show that generally more power was dissipated in the plasma instead of the sheath if the frequency of the substrate generator was decreased. This results in a significantly higher electron density at the higher frequency. The increase of mean ion energy, owing to lower sheath thickness, has to be taken into account as a second-order effect. In order to show the influence of frequency for process applications, the etch rate of SiO2 on silicon was determined in CF4. For the same generator power, there is no well-pronounced dependence of the etch rate of SiO2 on silicon (CF4) on the frequency. For the same bias voltage, the etch rate of SiO2 increases roughly with the frequency.

M. Klick; L. Eichhorn; W. Rehak; M. Kammeyer; H. Mischke

1999-01-01T23:59:59.000Z

63

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

64

Radio-frequency glow discharge spectrometry:: A critical review  

Science Journals Connector (OSTI)

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

Michael R. Winchester; Richard Payling

2004-01-01T23:59:59.000Z

65

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

Science Journals Connector (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 ... of electron energy balance takes into account ...

V. E. Moiseenko; Yu. S. Stadnik; A. I. Lysoivan; V. B. Korovin

2013-11-01T23:59:59.000Z

66

A multibeam radio-frequency ion source with a discharge chamber inside a resonator  

Science Journals Connector (OSTI)

The design of a multibeam ion source with a discharge chamber inside a half-wavelength radio-frequency (RF) resonator with a spiral load ... resonator. The RF oscillator operating at a frequency of 38 MHz is grou...

B. Yu. Bogdanovich; V. P. Zubovskii…

2008-09-01T23:59:59.000Z

67

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

Science Journals Connector (OSTI)

Lately the atmospheric pressure jet type coronaplasma 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 pressurecoronaplasmacharacteristics 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.

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

2011-01-01T23:59:59.000Z

68

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

69

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

70

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.

71

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

72

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

73

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

74

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

SciTech Connect (OSTI)

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

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

2000-03-01T23:59:59.000Z

75

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

76

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

77

Method of making radio frequency ion source 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.degree. C. to boil off the water from the binder, and then to about 750.degree. C.-850.degree. 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 apprxoimately 45% lead oxide.

Ehlers, Kenneth W. (Alamo, CA); Leung, Ka-Ngo (Hercules, CA)

1988-01-01T23:59:59.000Z

78

Radio-frequency plasma transducer for use in harsh environments  

SciTech Connect (OSTI)

We describe a compact transducer used to generate and modulate low-intensity radio-frequency atmospheric pressure plasma (RF-APP) for high temperature gap measurement and generation of air-coupled ultrasound. The new transducer consists of a quarter-wave transmission line where the ground return path is a coaxial solenoid winding. The RF-APP is initiated at the open end of the transmission line and stabilized by passive negative feedback between the electrical impedance of the plasma and the energy stored in the solenoid. The electrical impedance of the plasma was measured at the lower-voltage source end of the transducer, eliminating the need to measure kilovolt-level voltages near the discharge. We describe the use of a 7 MHz RF-APP prototype as a harsh-environment clearance sensor to demonstrate the suitability of plasma discharges for a common nondestructive inspection application. Clearance measurements of 0-5 mm were performed on a rotating calibration target with a measurement precision of 0.1 mm and a 20 kHz sampling rate.

May, Andrew; Andarawis, Emad [GE Global Research, 1 Research Circle, Niskayuna, New York 12309 (United States)

2007-10-15T23:59:59.000Z

79

Radio-frequency plasma transducer for use in harsh environments  

Science Journals Connector (OSTI)

We describe a compact transducer used to generate and modulate low-intensity radio-frequency atmospheric pressure plasma (RF-APP) for high temperature gap measurement and generation of air-coupled ultrasound. The new transducer consists of a quarter-wave transmission line where the ground return path is a coaxial solenoid winding. The RF-APP is initiated at the open end of the transmission line and stabilized by passive negative feedback between the electrical impedance of the plasma and the energy stored in the solenoid. The electrical impedance of the plasma was measured at the lower-voltage source end of the transducer eliminating the need to measure kilovolt-level voltages near the discharge. We describe the use of a 7 MHz RF-APP prototype as a harsh-environment clearance sensor to demonstrate the suitability of plasma discharges for a common nondestructive inspection application. Clearance measurements of 0 – 5 mm were performed on a rotating calibration target with a measurement precision of 0.1 mm and a 20 kHz sampling rate.

Andrew May; Emad Andarawis

2007-01-01T23:59:59.000Z

80

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

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

H- radio frequency source development at the Spallation Neutron Source  

SciTech Connect (OSTI)

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

Welton, Robert F [ORNL; Pennisi, Terry R [ORNL; Roseberry, Ron T [ORNL; Stockli, Martin P [ORNL

2012-01-01T23:59:59.000Z

82

Analytical model for the radio-frequency sheath  

Science Journals Connector (OSTI)

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

Uwe Czarnetzki

2013-12-03T23:59:59.000Z

83

Effect of resonance in external radio-frequency circuit on very high frequency plasma discharge  

SciTech Connect (OSTI)

A fully electromagnetic plasma model for an asymmetric capacitively coupled plasma discharge is used to understand the interaction between the external radio-frequency (rf) distributed circuit and the plasma. The plasma is excited using a 150 MHz rf source connected to the top electrode, the bottom electrode is connected to a shorted transmission line, and the electrodes are separated from the chamber walls through dielectric rings. Under typical conditions, the electron density peaks in the center of the plasma chamber due to the standing electromagnetic wave and the rf current from the top electrode primarily returns through the bottom electrode. When the electrical length of the bottom transmission line is adjusted such that it presents a large (open-circuit) impedance at the plasma chamber interface, the rf return current shifts from the bottom electrode to the chamber wall. As a consequence, the peak in electron density also moves from the center of the chamber toward its outer periphery.

Rauf, Shahid; Chen Zhigang; Collins, Ken [Applied Materials, Inc., 974 E. Arques Avenue, M/S 81517 Sunnyvale, California 94085 (United States)

2010-05-15T23:59:59.000Z

84

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

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

lines. In addition, we scale our results to the same assumed cosmology and radio frequency (408 MHz... Mon. Not. R. Astron. Soc. (2008) doi:10.1111j.1365-2966.2007.12752....

85

Electrical Features of Radio-frequency, Atmospheric-pressure, Bare-metallic-electrode Glow Discharges  

Science Journals Connector (OSTI)

Radio-frequency (RF), atmospheric-pressure glow discharge (APGD) plasmas with bare metallic electrodes have promising prospects in the fields of plasma-aided etching, deposition, disinfection and sterilization, ....

He-Ping Li; Wen-Ting Sun; Hua-Bo Wang; Guo Li…

2007-10-01T23:59:59.000Z

86

Negative ion-containing plasma in parallel-plate radio-frequency discharge in oxygen  

Science Journals Connector (OSTI)

The properties of a plasma in a parallel-plate radio frequency (rf) symmetric discharge of 13.56 MHz in oxygen have been investigated. The plasma contains negative ions. The temperature and density ... .6 eV, dep...

H. Amemiva; N. Yasuda; M. Endou

1994-09-01T23:59:59.000Z

87

Decontamination of VX Surrogate Malathion by Atmospheric Pressure Radio-frequency Plasma Jet  

Science Journals Connector (OSTI)

Decontamination of the VX surrogate (malathion) by the atmospheric pressure radio-frequency plasma jet (APPJ) was investigated. Optical emission ... the neutral gas temperature. The effects of RF input power and ...

Wen-Chao Zhu; Bai-Rong Wang; Hai-Ling Xi…

2010-06-01T23:59:59.000Z

88

Radio-frequency-induced optical gain in Pr3+:Y2SiO5  

Science Journals Connector (OSTI)

We report an observation of radio-frequency (RF)-induced transparency in an optically dense medium of Pr3+-doped Y2SiO5. We observed that the optical...

Ham, B S; Shahriar, M S; Hemmer, P R

1998-01-01T23:59:59.000Z

89

Radio-frequency Ar plasma treatment on muga silk fiber: correlation between physicochemical and surface morphology  

Science Journals Connector (OSTI)

Radio-frequency (RF) Ar plasma treatment is carried out on natural muga silk fibers in a capacitively coupled plasma reactor. The physical and thermal properties of the muga fibers are investigated at an RF power...

Dolly Gogoi; Joyanti Chutia…

2012-11-01T23:59:59.000Z

90

Characteristics of single and dual radio-frequency (RF) plasma sheaths  

Science Journals Connector (OSTI)

The characteristics of radio-frequency (RF) plasma sheaths have been topics of much scientific ... in the study of physical phenomena in dusty plasmas. The sheaths behave special properties under various ... as c...

Zhong-ling Dai; You-nian Wang

2006-06-01T23:59:59.000Z

91

Infrared radio-frequency double resonance of 13CH3OH  

Science Journals Connector (OSTI)

Infrared radio-frequency double-resonance spectroscopy has been carried out for 13CH3OH. Four K-type doublet transitions have been observed below 1 GHz, using the...

Petersen, J C

1987-01-01T23:59:59.000Z

92

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

93

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

94

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

95

Frequency effects on the electron density and {alpha}-{gamma} mode transition in atmospheric radio frequency discharges  

SciTech Connect (OSTI)

In this paper, a one-dimensional model is explored to investigate the frequency effects on the characteristics of atmospheric radio frequency discharges at a given power. The simulation data and analytical results show that the improvement of electron density can be observed with better discharge stability by increasing excitation frequency in an appropriate range. Using the analytical equations deduced from the model, the mean electron density could be inferred by means of the measured parameters. The {alpha}-{gamma} mode transition especially in high frequency discharges is also analytically discussed based on the theoretical equations.

Zhang Yuantao [Shandong Provincial Key Lab of UHV Technology and Gas Discharge Physics, School of Electrical Engineering, Shandong University, Jinan, Shandong Province 250061 (China); Cui Shaoyan [School of Mathematics and Information, Ludong University, Yantai, Shandong Province 264025 (China)

2011-08-15T23:59:59.000Z

96

Increased protein synthesis by cells exposed to a 1,800-MHz radio-frequency mobile phone electromagnetic field, detected by proteome profiling  

Science Journals Connector (OSTI)

To investigate whether or not low intensity radio frequency electromagnetic field exposure (RF-EME) associated...

Christopher Gerner; Verena Haudek…

2010-08-01T23:59:59.000Z

97

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

98

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

99

Radio frequency identification enabled wireless sensing for intelligent food logistics  

Science Journals Connector (OSTI)

...with short- or medium-range wireless in ISM band such as ZigBee and Bluetooth. It...have been several alternatives, such as fuel cells and thin-film batteries. Moreover...limitations as passive tags, they come at higher price levels and require batteries to operate...

Zhuo Zou; Qing Chen; Ismail Uysal; Lirong Zheng

2014-01-01T23:59:59.000Z

100

Radio frequency identification enabled wireless sensing for intelligent food logistics  

Science Journals Connector (OSTI)

...MPRV.2006.15 ) 18 Law, MK , A Bermak, and HC Luong...and AP Chandrakasan. 2007 An ultra low energy 12-bit rate-resolution...and L-R Zheng. 2010 An ultra-low-cost RFID tag with 1...system. In IEEE Int. Conf. on Ultra-Wideband, pp. 1-4...

2014-01-01T23:59:59.000Z

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.


101

Adversarial Model for Radio Frequency Identification Gildas Avoine  

E-Print Network [OSTI]

barcodes. One area of application for RFID tags is the management of stock and inventories in shops libraries in the United States have already adopted the RFID technology, e.g., the Santa Clara City Library]. The aim is to help customers to keep in touch wi

102

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

103

Propagation of Audio-Frequency Radio Waves to Great Distances  

Science Journals Connector (OSTI)

... distances from the source clearly showed that the main concentration of energy lay in the audio-frequency band below 10 kc./s. and that the higher-frequency components moved forward ... selective absorption, which, together with the low attenuation at the extreme ends of the audio-frequency range, accounts for the observed long-distance propagation characteristics of atmospherics1. As is ...

F. W. CHAPMAN; R. C. V. MACARIO

1956-05-19T23:59:59.000Z

104

Frequency Shift of Radio Signals in Curved Spacetimes  

E-Print Network [OSTI]

space . . . . . . . . . . . . . . . . . . . . . . . . . . 21 7.2 Schwarzschild space . . . . . . . . . . . . . . . 33 10 Another source of the shift in frequency 34 10.1 Reflection in a relativistically moving mirror

105

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

106

Radio-Frequency Inverters With Transmission-Line Input Networks  

E-Print Network [OSTI]

A soft-switching inverter topology (the Class Phi ) is presented which draws dc source current through a transmission line or a lumped-network approximation of a distributed line. By aligning the inverter switching frequency ...

Phinney, Joshua W.

107

Characteristics of radio-frequency, atmospheric-pressure glow discharges with air using bare metal electrodes  

SciTech Connect (OSTI)

In this letter, an induced gas discharge approach is proposed and described in detail for obtaining a uniform atmospheric-pressure glow discharge with air in a {gamma} mode using water-cooled, bare metal electrodes driven by radio-frequency (13.56 MHz) power supply. A preliminary study on the discharge characteristics of the air glow discharge is also presented in this study. With this induced gas discharge approach, radio-frequency, atmospheric-pressure glow discharges using bare metal electrodes with other gases which cannot be ignited directly as the plasma working gas, such as nitrogen, oxygen, etc., can also be obtained.

Wang Huabo; Sun Wenting; Li Heping; Bao Chengyu; Zhang Xiaozhang [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China)

2006-10-16T23:59:59.000Z

108

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

109

Magnetic field probes for use in radio frequency plasma  

SciTech Connect (OSTI)

An impedance analyzer has been used in the characterization of a magnetic induction probe (B-dot probe) for use in plasma. The role of the impedance analyzer was to determine the frequency response of a B-dot probe up to 100 MHz. The probe was specifically designed to take measurements in rf plasma driven at 13.56 MHz. Probe sensitivity and calibration are considered based on the impedance values obtained when a B-dot probe is swept over a wide frequency range. Effects such as unbalanced loads based on transmission line inductances and termination impedance are shown to be limiting factors on the probes useful frequency range. The use of an impedance analyzer allows these effects to readily be characterized.

Reilly, Michael P.; Miley, George H. [Department of Nuclear, Plasma, and Radiological Engineering, University of Illinois at Urbana-Champaign, 104 S. Wright Street, 216 Talbot Laboratory, MC-234 Urbana, Illinois 61801 (United States); Lewis, William [ERC Inc. Knight High School, 37423 70th Street East, Palmdale, California 93552 (United States)

2009-05-15T23:59:59.000Z

110

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

111

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.

112

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

113

A high-performance cryogenic amplifier based on a radio-frequency single electron transistor  

E-Print Network [OSTI]

A high-performance cryogenic amplifier based on a radio-frequency single electron transistor K, Sweden Received 23 May 2002; accepted 24 October 2002 We demonstrate a high-performance cryogenic-chip integrability, make it a good candidate for a general-purpose cryogenic amplifier for high impedance sources. We

Segall, Ken

114

Radio-Frequency Current Drive in a Fusion-Producing Plasma  

Science Journals Connector (OSTI)

A method for driving current in a fusion-producing plasma is proposed. Radio-frequency power is used to prohibit fusion-produced energetic particles from slowing down isotropically or to push them in a preferential direction. As a result, a net plasma current is generated whose efficiency is comparable to other current drive schemes.

D. K. Bhadra and C. Chu

1982-06-28T23:59:59.000Z

115

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

E-Print Network [OSTI]

of the radio frequency tones by laser-cavity detuning and laser power levels, confirmed by the CMT simulations crystal cavity is removed by buffered oxide wet etching. Inverse tapered couplers with an oxide over-cladding the CW coherent transverse-electric light from a tunable laser onto chip through polarization control

Hone, James

116

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.

117

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

118

Plasma acceleration from radio-frequency discharge in dielectric capillary A. Dunaevskya  

E-Print Network [OSTI]

Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543 Received 19 August 2005; accepted 22Plasma acceleration from radio-frequency discharge in dielectric capillary A. Dunaevskya Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08540 Y. Raitses and N. J. Fisch Princeton

119

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

120

Radio-frequency stabilization of a nonequilibrium plasma accelerator  

SciTech Connect (OSTI)

Results of experimental studies of the effect of an external RF field on the excitation of oscillations in a magnetoplasmadynamic plasma accelerator are presented. It is found that applying an RF field can suppress the drift component of low-frequency oscillations in the ejected plasma flow. The experimental data agree with the concept of stabilization of the plasma accelerator by the magnetic component of the field generated by the RF current loop. The conditions under which the RF field stabilizes the generation of the plasma flow are determined, and the factors limiting the stabilization efficiency are revealed.

Kirdyashev, K. P. [Russian Academy of Sciences, Kotel'nikov Institute of Radio Engineering and Electronics (Fryazino Branch) (Russian Federation)

2011-08-15T23:59:59.000Z

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.


121

Fourier synthesis and timbre tuning of radio frequency nanomechanical pulses  

E-Print Network [OSTI]

The concept of Fourier synthesis provides the foundation for both everyday consumer electronic products and fundamental research. In the latter, so called pulse shaping is nowadays key to dynamically initialize, probe and manipulate the state of classical or quantum systems. In nuclear magnetic resonance, for instance, shaped pulses have a long-standing tradition and the underlying fundamental concepts have subsequently been successfully extended to optical frequencies and even to implement quantum gate operations. Transfer of these paradigms to nanomechanical systems, requires tailored nanomechanical waveforms (NMWFs) for mechanically mediated coherent control schemes. Here, we report on a novel additive Fourier synthesizer for NMWFs based on monochromatic surface acoustic waves (SAWs). As a proof of concept, we electrically synthesize four different elementary NMWFs from a fundamental SAW at $ f_1 \\sim 150$ MHz using a superposition of up to three discrete harmonics $f_n$. We employ these shaped pulses to i...

Schülein, Florian J R; Atkinson, Paola; Schmidt, Oliver G; Trotta, Rinaldo; Rastelli, Armando; Wixforth, Achim; Krenner, Hubert J

2014-01-01T23:59:59.000Z

122

Discharge ignition characteristics of pulsed radio-frequency glow discharges in atmospheric helium  

Science Journals Connector (OSTI)

An experimental study of radio-frequency (15 MHz) glow discharges in atmospheric helium modulated by pulses with repetition frequency of 500 kHz and duty cycle of 6% and 8% is presented in this paper. In each discharge burst the discharge is restricted to operate in ignition phase with duration of one or two radio-frequency cycles. The ignition characteristics in terms of spatial-temporal evolution of discharge interelectrode structure and optical emission intensity are investigated by time resolved imaging. Optical emission intensities at lines of 706 and 777 nm are used to capture clearly the temporal evolution of energetic electrons and active specie of atom oxygen generated in discharge.

Jianjun Shi; Yeqing Cai; Jie Zhang; Ke Ding; Jing Zhang

2009-01-01T23:59:59.000Z

123

Discharge ignition characteristics of pulsed radio-frequency glow discharges in atmospheric helium  

SciTech Connect (OSTI)

An experimental study of radio-frequency (15 MHz) glow discharges in atmospheric helium modulated by pulses with repetition frequency of 500 kHz and duty cycle of 6% and 8% is presented in this paper. In each discharge burst, the discharge is restricted to operate in ignition phase with duration of one or two radio-frequency cycles. The ignition characteristics in terms of spatial-temporal evolution of discharge interelectrode structure and optical emission intensity are investigated by time resolved imaging. Optical emission intensities at lines of 706 and 777 nm are used to capture clearly the temporal evolution of energetic electrons and active specie of atom oxygen generated in discharge.

Shi Jianjun; Cai Yeqing; Zhang Jie; Ding Ke; Zhang Jing [State Key Lab for Modification of Chemical Fibers and Polymer Materials, College of Material Science and Engineering, and College of Science, Donghua University, Shanghai 201620 (China)

2009-07-15T23:59:59.000Z

124

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

125

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

126

Discharge characteristics of atmospheric-pressure radio-frequency glow discharges with argon/nitrogen  

SciTech Connect (OSTI)

In this letter, atmospheric-pressure glow discharges in {gamma} mode with argon/nitrogen as the plasma-forming gas using water-cooled, bare copper electrodes driven by radio-frequency power supply at 13.56 MHz are achieved. The preliminary studies on the discharge characteristics show that, induced by the {alpha}-{gamma} coexisting mode or {gamma} mode discharge of argon, argon-nitrogen mixture with any mixing ratios, even pure nitrogen, can be employed to generate the stable {gamma} mode radio-frequency, atmospheric-pressure glow discharges and the discharge voltage rises with increasing the fraction of nitrogen in the argon-nitrogen mixture for a constant total gas flow rate.

Wang Huabo; Sun Wenting; Li Heping; Bao Chengyu; Gao Xing; Luo Huiying [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); School of Public Health and Family Medicine, Capital University of Medical Sciences, Beijing 100069 (China); Beijing Center for Diseases Control and Prevention, Beijing 100013 (China)

2006-10-16T23:59:59.000Z

127

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

128

Evolution of a Dust Void in a Radio-Frequency Plasma Sheath  

Science Journals Connector (OSTI)

The onset and growth of a dust void are investigated in a radio-frequency (rf) sheath of a capacitively coupled argon plasma. A circularly symmetric void emerges and grows with increasing rf power and pressure in the central region of the dust cloud levitating in the sheath. Experimental measurements of the void diameter are compared with the predictions of a simple phenomenological theory, based on a balance of forces on dust grains.

R. P. Dahiya; G. V. Paeva; W. W. Stoffels; E. Stoffels; G. M. W. Kroesen; K. Avinash; A. Bhattacharjee

2002-08-27T23:59:59.000Z

129

CW 100 kW radio frequency-free-electron laser design at 10. mu. m  

SciTech Connect (OSTI)

This paper describes the 100 kW CW radio frequency-free-electron last at 10{mu}m to be built at Boeing Defense and Space Group in collaboration with Los Alamos National Laboratory. The authors discuss the criteria which led to the selection of the operating point, the single-accelerator master-oscillator and power-amplifier configuration, the goals of this experiment, and the expected performance.

Parazzoli, C.G.; Rodenburg, R.E.; Romero, J.B.; Adamski, J.L.; Pistoresi, D.J.; Shoffstall, D.R. (Boeing Defense and Space Group, Seattle, WA (US)); Quimby, D.C. (STI Optronics, Inc., Bellevue, WA (US))

1991-12-01T23:59:59.000Z

130

Modes in a pulse-modulated radio-frequency dielectric-barrier glow discharge  

SciTech Connect (OSTI)

This letter reports an experimental study of a pulse-modulated radio-frequency dielectric-barrier discharge in atmospheric helium. By controlling the duty cycle at a modulation frequency of 10 and 100 kHz, the 13.56 MHz discharge is shown to operate in three different glow modes: the continuum mode, the discrete mode, and the transition mode. By investigating plasma ignition, residual electrons during power off are found to affect different glow modes. Duty cycle dependences of power density, gas temperature, optical emission intensities at 706 and 777 nm are used to capture clearly the characteristics of the three glow modes.

Shi, J. J.; Zhang, J.; Qiu, G. [College of Science, Donghua University, Shanghai 201620 (China); Walsh, J. L.; Kong, M. G. [Department of Electronic and Electrical Engineering, Loughborough University, Loughborough, Leicestershire LE11 3TU (United Kingdom)

2008-07-28T23:59:59.000Z

131

Modes in a pulse-modulated radio-frequency dielectric-barrier glow discharge  

Science Journals Connector (OSTI)

This letter reports an experimental study of a pulse-modulated radio-frequency dielectric-barrier discharge in atmospheric helium. By controlling the duty cycle at a modulation frequency of 10 and 100 kHz the 13.56 MHz discharge is shown to operate in three different glow modes: the continuum mode the discrete mode and the transition mode. By investigating plasma ignition residual electrons during power off are found to affect different glow modes. Duty cycle dependences of power density gas temperature optical emission intensities at 706 and 777 nm are used to capture clearly the characteristics of the three glow modes.

J. J. Shi; J. Zhang; G. Qiu; J. L. Walsh; M. G. Kong

2008-01-01T23:59:59.000Z

132

Measurements and modeling of radio frequency field structures in a helicon plasma  

SciTech Connect (OSTI)

Measurements of the radio frequency (rf) field structure, plasma density, and electron temperature are presented for a 1 kW argon helicon plasma source. The measured profiles change considerably when the equilibrium magnetic field is reversed. The measured rf fields are identified as fields of radially localized helicon waves, which propagate in the axial direction. The rf field structure is compared to the results of two-dimensional cold plasma full-wave simulations for the measured density profiles. Electron collision frequency is adjusted in the simulations to match the simulated and measured field profiles. The resulting frequency is anomalously high, which is attributed to the excitation of an ion-acoustic instability. The calculated power deposition is insensitive to the collision frequency and accounts for most of the power supplied by the rf-generator.

Lee, C. A. [University of Texas, Austin; Chen, Guangye [ORNL; Arefiev, A. V. [University of Texas, Austin; Bengtson, R. D. [University of Texas, Austin; Breizman, B. N. [University of Texas, Austin

2011-01-01T23:59:59.000Z

133

Frequency dependence of microparticle charge in a radio frequency discharge with Margenau electron velocity distribution  

SciTech Connect (OSTI)

rf discharges are widely used in complex plasma experiments. In this paper, we theoretically investigate the dependence of the particle floating potential on the discharge frequency, assuming the model Margenau expression for the electron velocity distribution function. In doing so we use the orbital motion limited cross section to calculate the electron flux to the particle and collision enhanced collection approximation for the ion flux to the particle. The floating potential is then obtained from the flux balance condition. It is shown that for typical plasma conditions in laboratory rf discharges, normalized floating potential grows with increase of the discharge frequency in collisionless regime and decreases in weakly collisional regime. However, variations in the floating potential are usually small when plasma parameters do not depend on the rf frequency.

Du, Cheng-Ran; Khrapak, Sergey A.; Antonova, Tetyana; Steffes, Bernd; Thomas, Hubertus M.; Morfill, Gregor E. [Max Plank Institute for Extraterrestrial Physics, Garching 85741 (Germany)

2011-01-15T23:59:59.000Z

134

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

135

Studies on the Matching Network of the High Power Radio Frequency Transmitter for the NBI RF Ion Source  

Science Journals Connector (OSTI)

A radio frequency (RF) driven ion source has been developed at ASIPP (Institute of Plasma Physics, CAS) for the neutral beam injector with a 1 MHz, 25 kW RF power supply system. The paper describes the studies pe...

Renxue Su; Zhimin Liu; Yahong Xie; Yuqian Chen; Yuming Gu…

2014-08-01T23:59:59.000Z

136

High rate deposition of microcrystalline silicon films by high-pressure radio frequency plasma enhanced chemical vapor deposition (PECVD)  

Science Journals Connector (OSTI)

Hydrogenated microcrystalline silicon (?c-Si:H) thin films were prepared by high-pressure radio-frequency (13.56 MHz) plasma enhanced chemical vapor deposition (rf-PECVD) with a screened plasma. The deposition ra...

BingQing Zhou; MeiFang Zhu; FengZhen Liu…

2008-04-01T23:59:59.000Z

137

Time?differential radio?frequency muon spin resonance (TD?RF?SR) technique at a pulsed muon beam  

Science Journals Connector (OSTI)

Longitudinal?field ?SR methods, e.g., radio?frequency ?+...spin resonance (RF?SR), are well suited to investigate dynamic processes that destroy the phase coherence of the muon spin ensemble. Additional informati...

R. Scheuermann; J. Schmidl; A. Seeger; Th. Stammler; D. Herlach…

138

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

139

The recovery of glow-plasma structure in atmospheric radio frequency microplasmas at very small gaps  

Science Journals Connector (OSTI)

In atmospheric radio frequency discharges at 13.56 MHz with the electrode gap reduced the sheath region eventually occupies a main portion of the electrode spacing and the bulk plasma region is significantly compressed. The computational results in this letter based on a one-dimensional fluid model show that by increasing the excitation frequency over 13.56 MHz the traditional glow-plasma structure could gradually recover even at very small sizes with a well defined quasineutral plasma region and the electron density is improved but the electric fields in sheath region are reduced. This study indicates that the excitation frequency can be used to modulate the discharge structure and then tailor the plasma-surface interaction in atmospheric microplasmas.

Yuan-Tao Zhang; Wan-Li Shang

2011-01-01T23:59:59.000Z

140

The recovery of glow-plasma structure in atmospheric radio frequency microplasmas at very small gaps  

SciTech Connect (OSTI)

In atmospheric radio frequency discharges at 13.56 MHz, with the electrode gap reduced, the sheath region eventually occupies a main portion of the electrode spacing and the bulk plasma region is significantly compressed. The computational results in this letter based on a one-dimensional fluid model show that by increasing the excitation frequency over 13.56 MHz, the traditional glow-plasma structure could gradually recover even at very small sizes with a well defined quasineutral plasma region, and the electron density is improved but the electric fields in sheath region are reduced. This study indicates that the excitation frequency can be used to modulate the discharge structure and then tailor the plasma-surface interaction in atmospheric microplasmas.

Zhang Yuantao [Shandong Provincial Key Lab of UHV Technology and Gas Discharge Physics, School of Electrical Engineering, Shandong University, Jinan 250061, Shandong Province (China); Shang Wanli [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, Sichuan Province (China)

2011-11-15T23:59:59.000Z

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

The JT-60 radio-frequency heating system: description and R&D results  

Science Journals Connector (OSTI)

A system feature of the radio-frequency (RF) heating system for JT-60 is described. This system contains three units Lower Hybrid Range of Frequencies (LHRF) and one unit Ion Cyclotron Range of Frequencies (ICRF) heating systems. The LHRF heating system produces about 24 MW at 2 \\{GHz\\} of RF power using 24 high power klystrons and the ICRF heating system does 6 MW at 120 \\{MHz\\} of RF power using 8 high power tetrodes. Development of a high power klystron for the LHRF heating system and the coupling system for high power density of the transmission are performed for the construction of the RF heating system for JT-60. Japan Atomic Energy Research Institute (JAERI) has already constructed the RF heating system for JT-60 and is now performing the coupling test to JT-60 plasma.

T. Nagashima; K. Uehara; H. Kimura; T. Imai; T. Fujii; K. Sakamoto; Y. Ikeda; M. Saigusa; N. Suzuki; M. Honda; K. Yokokura; K. Kiyono; M. Sawahata; K. Suganuma; M. Seki; H. Shirakata

1987-01-01T23:59:59.000Z

142

Retarding field analyzer for ion energy distribution measurements at a radio-frequency biased electrode  

SciTech Connect (OSTI)

A retarding field energy analyzer designed to measure ion energy distributions impacting a radio-frequency biased electrode in a plasma discharge is examined. The analyzer is compact so that the need for differential pumping is avoided. The analyzer is designed to sit on the electrode surface, in place of the substrate, and the signal cables are fed out through the reactor side port. This prevents the need for modifications to the rf electrode--as is normally the case for analyzers built into such electrodes. The capabilities of the analyzer are demonstrated through experiments with various electrode bias conditions in an inductively coupled plasma reactor. The electrode is initially grounded and the measured distributions are validated with the Langmuir probe measurements of the plasma potential. Ion energy distributions are then given for various rf bias voltage levels, discharge pressures, rf bias frequencies - 500 kHz to 30 MHz, and rf bias waveforms - sinusoidal, square, and dual frequency.

Gahan, D.; Hopkins, M. B. [National Centre for Plasma Science and Technology, Dublin City University, Glasnevin, Dublin 9 (Ireland); Dolinaj, B. [Impedans Ltd., Invent Centre, Dublin City University, Glasnevin, Dublin 9 (Ireland)

2008-03-15T23:59:59.000Z

143

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

144

Radio frequency coupling apparatus and method for measuring minority carrier lifetimes in semiconductor materials  

DOE Patents [OSTI]

An apparatus for measuring the minority carrier lifetime of a semiconductor sample using radio-frequency coupling. The measuring apparatus includes an antenna that is positioned a coupling distance from a semiconductor sample which is exposed to light pulses from a laser during sampling operations. A signal generator is included to generate high frequency, such as 900 MHz or higher, sinusoidal waveform signals that are split into a reference signal and a sample signal. The sample signal is transmitted into a sample branch circuit where it passes through a tuning capacitor and a coaxial cable prior to reaching the antenna. The antenna is radio-frequency coupled with the adjacent sample and transmits the sample signal, or electromagnetic radiation corresponding to the sample signal, to the sample and receives reflected power or a sample-coupled-photoconductivity signal back. To lower impedance and speed system response, the impedance is controlled by limiting impedance in the coaxial cable and the antenna reactance. In one embodiment, the antenna is a waveguide/aperture hybrid antenna having a central transmission line and an adjacent ground flange. The sample-coupled-photoconductivity signal is then transmitted to a mixer which also receives the reference signal. To enhance the sensitivity of the measuring apparatus, the mixer is operated to phase match the reference signal and the sample-coupled-photoconductivity signal.

Johnston, Steven W. (Golden, CO); Ahrenkiel, Richard K. (Lakewood, CO)

2002-01-01T23:59:59.000Z

145

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

146

Improvement of isentropic efficiency of a magnetohydrodynamic power generator by radio-frequency preionization  

Science Journals Connector (OSTI)

We describe the effect of a radio-frequency (rf) power application on the performance of a magnetohydrodynamic(MHD) electrical power generator as determined through shock-tunnel-based experiments and quasi-three-dimensional numerical simulations. The temporal plasma-fluid behavior the one-dimensional plasma-fluid structure the enthalpy-entropy diagram the quality of the energy conversion efficiency and the energy flow in the power-generating system are investigated. Preionization assistance by a small amount of rf power drastically changes the entire MHD power-generating system; the MHD extraction length is considerably extended and the isentropic efficiency is significantly improved.

Tomoyuki Murakami; Yoshihiro Okuno

2009-01-01T23:59:59.000Z

147

Numerical modeling of dust particle configurations in a cylindrical radio-frequency plasma reactor  

Science Journals Connector (OSTI)

In the present work, first, plasma phase variables in a cylindrical radio-frequency (rf) plasma reactor are numerically solved using the local field approximation model. Then, equilibrium configurations of a few interacting (sub-)micron-sized dust particles are obtained by integrating the particles equations for their motion and charge, accounting for the various forces acting on each particle in a three-dimensional Lagrangian framework. Direct comparison of the results with experiment demonstrates excellent qualitative agreement. Based on the ion focus phenomenon, a physical model is formulated and proven successful in simulating the vertically aligned structures.

M. Davoudabadi and F. Mashayek

2007-11-30T23:59:59.000Z

148

Study of the change of electron temperature inside magnetic island caused by localized radio frequency heating  

SciTech Connect (OSTI)

The change in the electron temperature inside magnetic island caused by localized radio frequency (rf) heating is studied numerically by solving the two-dimensional energy transport equation, to investigate the dependence of the temperature change on the location and width of the rf power deposition along the minor radius and the helical angle, the island width, and the ratio between the parallel and the perpendicular heat conductivity. Based on obtained numerical results, suggestions for optimizing the island stabilization by localized rf heating are made.

Yang, J.; Zhu, S. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Center for Magnetic Fusion Theory, Chinese Academy of Sciences, Hefei 230031 (China); Yu, Q. [Max-Planck-Institute fuer Plasmaphysik, EURATOM Association, Garching 85748 (Germany); Zhuang, G. [College of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

2010-05-15T23:59:59.000Z

149

Evolution of Discharge Structure in Capacitive Radio-Frequency Atmospheric Microplasmas  

Science Journals Connector (OSTI)

Conventional radio-frequency (rf) nonthermal atmospheric plasmas are generated in a millimeter gap. In this Letter, we present a self-consistent numerical study of rf atmospheric microplasmas in a submillimeter gap comparable to their sheath thickness. It is shown that the narrow electrode gap deforms the discharge structure, ultimately removing the bulk-plasma region and disabling electron trapping. Significantly, these properties permit rf atmospheric microplasmas to operate at very high current densities thus simultaneously achieving higher stability and greater chemical reactivity.

J. J. Shi and M. G. Kong

2006-03-16T23:59:59.000Z

150

Theory of shear suppression of edge turbulence by externally driven radio-frequency waves  

Science Journals Connector (OSTI)

Here, we propose and analyze a technique for active suppression of tokamak edge turbulence. Suppression occurs due to the effects of a sheared radial electric field generated by externally driven radio-frequency waves. Plasma flow is induced by radially varying wave-driven Reynolds and magnetic stresses, and opposed by neoclassical damping. For Alfvénic flow drive, the predicted shear flow profile is determined by ion inertia and electron dissipation effects. Results indicate that a modest amount of absorbed power is required for edge-turbulence suppression. More generally, several novel results in the theory of momentum transport by electromagnetic fluctuations are presented.

G. G. Craddock and P. H. Diamond

1991-09-16T23:59:59.000Z

151

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

152

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

153

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

154

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

155

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

156

Phase-Resolved Measurements of Ion Velocity in a Radio-Frequency Sheath Brett Jacobs,1,* Walter Gekelman,1  

E-Print Network [OSTI]

-induced fluorescence in a commercial plasma process- ing tool. Discharge parameters were such that the 2.2 MHz rf upon the ratio of the ion transit time through the sheath to the rf period (ion=rf) [11]. In the high-frequencyPhase-Resolved Measurements of Ion Velocity in a Radio-Frequency Sheath Brett Jacobs,1,* Walter

California at Los Angles, University of

157

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

E-Print Network [OSTI]

2-dimensional ion velocity distributions measured by laser-induced fluorescence above a radio-frequency cm diameter, 2.2 MHz-biased silicon wafer in a commercial inductively coupled plasma processing rf frequencies,5­7,18 non-sinusoidal waveforms8 and pulsed power.9,19 Control of IEDs in many

California at Los Angles, University of

158

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.

159

Density-dependent response of an ultracold plasma to few-cycle radio-frequency pulses  

Science Journals Connector (OSTI)

Ultracold neutral plasmas exhibit a density-dependent resonant response to applied radio-frequency (rf) fields in the frequency range of several to hundreds of megahertz for achievable densities. We have conducted measurements where short bursts of an rf fieldwere applied to these plasmas, with pulse durations as short as two cycles. We still observed a density-dependent resonant response to these short pulses, but the time scale of the response is too short to be consistent with local heating of electrons in the plasma from collisions under a range of experimental parameters. Instead, our results are consistent with rapid energy transfer to individual electrons from electric fields resulting from an overall displacement of the electron cloud from the ions during the collective motion of the electrons. This collective motion was also observed by applying two sharp electric field pulses separated in time to the plasma. These measurements demonstrate the importance of collective motion in the energy transport in these systems.

Truman M. Wilson; Wei-Ting Chen; Jacob L. Roberts

2013-01-14T23:59:59.000Z

160

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

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

Contactless measurement of nonlinear conductivity in the radio-frequency range  

E-Print Network [OSTI]

We have developed a system for contactless measurement of nonlinear conductivity in the radio-frequency band, and over a wide temperature range. A non-resonant circuit is used to electrically excite the sample, and the induced signal is detected by a resonant circuit whose natural frequency matches higher harmonics of the excitation. A simple modification of the probe allows non-resonant detection suitable for stronger signals. Two measurement procedures are proposed that allow significant excitation power variation, up to 150 W. The apparatus has been validated trough the measurement of the nonlinear response at the superconducting transition of a high-Tc superconductor, and the nematic transition of an iron pnictide.

Došli?, Marija; Požek, Miroslav

2014-01-01T23:59:59.000Z

162

Sheath model for radio-frequency-biased, high-density plasmas valid for all ?/?i  

Science Journals Connector (OSTI)

A model is proposed for sheaths in high-density discharges, with radio-frequency (rf) bias applied at frequencies ? comparable to ?i, the ion plasma frequency at the edge of the sheath. The model treats ion dynamics using fluid equations, including all time-dependent terms. Model predictions for current, impedance, and power were compared to measurements performed in high-density discharges in argon at 1.33 Pa (10 mTorr) at rf bias frequencies from 0.1 to 10 MHz (?/?i from 0.006 to 1.8) and rf bias voltages from 1 to 200 V. Model predictions were in good agreement with measurements, much better than that obtained by models that neglect time-dependent ion dynamics. In particular, differences of as much as 40–50 % between power measurements and the power predicted by previous models are now explained and eliminated. The model also explains why methods of extracting plasma parameters from electrical measurements using previous sheath models may fail, and it suggests more accurate methods of extracting these parameters.

Mark A. Sobolewski

2000-12-01T23:59:59.000Z

163

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

164

Characterization and tribological application of diamond-like carbon (DLC) films prepared by radio-frequency plasma-enhanced chemical vapor deposition (RF-PECVD) technique  

Science Journals Connector (OSTI)

Diamond-like carbon (DLC) films were successfully prepared on glass substrates and surfaces of selenium drums via radio frequency plasma enhanced chemical vapor deposition method. The...

Ning Cao; Zhen-yi Fei; Yong-xin Qi; Wen-wen Chen…

2009-12-01T23:59:59.000Z

165

Reclamation of niobium compounds from ionic liquid electrochemical polishing of superconducting radio frequency cavities  

SciTech Connect (OSTI)

Recent research has shown that choline chloride (vitamin B4)-based solutions can be used as a greener alternative to acid-based electrochemical polishing solutions. This study demonstrated a successful method for electrochemical deposition of niobium compounds onto the surface of copper substrates using a novel choline chloride-based ionic liquid. Niobium ions present in the ionic liquid solution were dissolved into the solution prior to deposition via electrochemical polishing of solid niobium. A black coating was clearly visible on the surface of the Cu following deposition. This coating was analyzed using scanning electron microscopy (SEM), electron dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), and X-ray fluorescence spectroscopy (XRF). This ionic liquid-based electrochemical deposition method effectively recycles previously dissolved niobium from electrochemical polishing of superconducting radio frequency (SRF) cavities.

Wixtrom, Alex I. [Christopher Newport University, Newport News, VA (United States); Buhler, Jessica E. [Christopher Newport University, Newport News, VA (United States); Reece, Charles E. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Abdel-Fattah, Tarek M. [Christopher Newport University, Newport News, VA (United States)

2013-06-01T23:59:59.000Z

166

Influence of oxygen traces on an atmospheric-pressure radio-frequency capacitive argon plasma discharge  

Science Journals Connector (OSTI)

An atmospheric-pressure capacitive discharge source driven by radio-frequency power supply at 13.56 MHz has been developed experimentally that is capable of producing a homogeneous and cold glow discharge in O2/Ar. With respect to the influence of oxygen component when diluted into argon plasmadischarge on the dischargecharacteristics the measurements of the electrical parameters (impedance phase angle resistance and reactance) are made systematically and the densities of the metastable and resonant state of argon are determined by means of optical emission spectroscopy(OES). It is shown that the admixture of oxygen into argon plasma not only changes the electric characteristics but also alters the optical emission spectra greatly due to strong interaction between the oxygen content and the argon in the plasma environment.

Shou-Zhe Li; Qi Wu; Wen Yan; Dezhen Wang; Han S. Uhm

2011-01-01T23:59:59.000Z

167

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

168

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

169

Spatial distribution of the plasma parameters in a radio-frequency driven negative ion sourcea)  

Science Journals Connector (OSTI)

Results from initial stage of modeling of the SPIDER source of negative hydrogen/deuterium ions currently under development in Consorzio RFX (Padova) regarding ITER are presented. A 2D model developed within the fluid plasma theory for low-pressure discharges (free-fall regime maintenance) is applied to the gas-discharge conditions planned and required for the SPIDER source: gas pressure of 0.3 Pa and radio-frequency (rf) power of 100 kW absorbed in a single driver. The results are for the spatial distribution of the plasma characteristics (charged particle densities electron temperature and electron energy flux plasma potential and dc electric field) with conclusions for the role of the electron energy flux in the formation of the discharge structure.

D. Todorov; Kh. Tarnev; Ts. Paunska; St. Lishev; A. Shivarova

2014-01-01T23:59:59.000Z

170

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

171

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

172

A large gap of radio frequency dielectric barrier atmospheric pressure glow discharge  

SciTech Connect (OSTI)

A large gap was acquired between electrodes (up to 5.5 mm) of Ar atmospheric pressure glow discharge in radio frequency dielectric barrier discharge (rf-DBD). The discharge of Ar plasma was characterized by I-V curve and Lissajous plot, and the effective power of the discharge was calculated based on the measured Lissajous plot and found to be higher than 90% of the input power. To gain a thorough understanding of the mechanism, the rf-DBD with a single dielectric barrier layer operating in gamma mode glow discharge of N{sub 2} plasma was diagnosed in spatial resolution through optical emission spectroscopy. It was concluded that secondary electron emission might be responsible for the sustainable glow discharge in the large gap rf-DBD plasma.

Li, B.; Chen, Q.; Liu, Z. W. [Laboratory of Plasma Physics and Materials, Beijing Institute of Graphic Communication, Beijing 102600 (China)

2010-01-25T23:59:59.000Z

173

Structure control of carbon nanotubes using radio-frequency plasma enhanced chemical vapor deposition  

Science Journals Connector (OSTI)

Carbon nanotube structures such as tube diameter, growth site, and formation density are controlled using radio-frequency (RF, 13.56 MHz) plasma enhanced chemical vapor deposition (RF-PECVD) method. We have produced uniformly well-aligned multi-walled carbon nanotubes (MWNTs) grown over the large scale area and linearly arrayed \\{MWNTs\\} grown in a selected area without any highly-sophisticated patterning process. In our RF-PECVD experiment, furthermore, individually grown single-walled carbon nanotubes (SWNTs) or their thin bundles are synthesized for the first time within the scope of the PECVD methods. These results indicate that PECVD method provides the high potential for the further development of nano-technology.

T. Kato; G.-H. Jeong; T. Hirata; R. Hatakeyama

2004-01-01T23:59:59.000Z

174

Temporally resolved ion velocity distribution measurements in a radio-frequency plasma sheath  

SciTech Connect (OSTI)

The ion velocity distribution function (IVDF) above and within a radio-frequency (RF) biased plasma sheath is studied experimentally with a pulsed laser-induced fluorescence diagnostic in an industrial plasma etch tool. Temporally resolved measurements taken at eight different phases of the 2.2 MHz bias waveform show that the ion dynamics vary dramatically throughout the RF cycle (the ratio of the average ion transit time through the sheath to the RF period is {tau}{sub ion}/{tau}{sub RF} = 0.3). The position of the presheath/sheath edge is constant throughout the RF cycle and the time-averaged ion flux is conserved within the sheath region. The characteristic bimodal structure of the time-averaged ion distributions found in previous experiments is observed to arise from the time-dependent ion dynamics, in accord with existing theory. The large temporal variation of the IVDF has implications for the plasma chemistry and etching quality.

Jacobs, B.; Gekelman, W.; Pribyl, P. [University of California, Los Angeles, California 90095 (United States); Barnes, M. [MS Barnes Engineering, San Ramon, California 94583 (United States)

2011-05-15T23:59:59.000Z

175

Numerical investigation of pulse-modulated atmospheric radio frequency discharges in helium under different duty cycles  

SciTech Connect (OSTI)

Experiments observed that the pulse duty cycle has effects on the plasma homogeneity in pulse-modulated radio frequency (rf) discharges. In this paper, pulse-modulated rf (13.56 MHz) helium discharges are theoretically investigated using a two dimensional fluid model. With the pulse period being fixed to 15 {mu}s, it is found that when the pulse-on duration is over 4 {mu}s, i.e., the duty cycle is larger than approximately 27%, the discharge transits from an inhomogeneous to a homogeneous mode in every specific part of each pulse cycle under currently-used simulation parameters. More quantitative analysis shows that the discharge becomes more homogeneous as the duty cycle is increased but does not reach complete homogeneity. Possible reasons for the homogeneity improvement are discussed.

Sun Jizhong; Ding Zhengfen; Li Xuechun; Wang Dezhen [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116023 (China); Wang Qi [Dalian Institute of Semiconductor Technology, School of Electronics Science and Technology, Dalian University of Technology, Dalian 116023 (China)

2011-12-15T23:59:59.000Z

176

Radio-frequency sheath-plasma interactions with magnetic field tangency points along the sheath surface  

SciTech Connect (OSTI)

Computer simulations of radio-frequency (RF) waves propagating across a two-dimensional (2D) magnetic field into a conducting boundary are described. The boundary condition for the RF fields at the metal surface leads to the formation of an RF sheath, which has previously been studied in one-dimensional models. In this 2D study, it is found that rapid variation of conditions along the sheath surface promote coupling of the incident RF branch (either fast or slow wave) to a short-scale-length sheath-plasma wave (SPW). The SPW propagates along the sheath surface in a particular direction dictated by the orientation of the magnetic field with respect to the surface, and the wave energy in the SPW accumulates near places where the background magnetic field is tangent to the surface.

Kohno, H. [Department of Physics, Lehigh University, 16 Memorial Drive East, Bethlehem, Pennsylvania 18015 (United States)] [Department of Physics, Lehigh University, 16 Memorial Drive East, Bethlehem, Pennsylvania 18015 (United States); Myra, J. R.; D'Ippolito, D. A. [Lodestar Research Corporation, 2400 Central Avenue P-5, Boulder, Colorado 80301 (United States)] [Lodestar Research Corporation, 2400 Central Avenue P-5, Boulder, Colorado 80301 (United States)

2013-08-15T23:59:59.000Z

177

Particle-in-cell simulation of hydrogen discharge driven by combined radio frequency and pulse sources  

SciTech Connect (OSTI)

A particle-in-cell plus Monte Carlo collision model is employed to investigate the low pressure hydrogen capacitive discharge driven by combined radio frequency (rf) and pulse sources. This work focuses on the evolutions of electron energy and density in the discharge to illustrate the role that a short pulse source plays. The simulation results show that an extra short pulse source can modulate the electron energy effectively: in the early and late pulse-on times, the electron energy is much higher than that in the single rf source discharge; during the pulse-off time, the electron energy can drop gradually to a low value. It is also found that a few peaks of attenuated electron energy appear periodically just after the pulse voltage drops to zero. The similar phenomena can also be found in the production rate of highly vibrationally excited hydrogen molecules. Physical mechanisms responsible for these phenomena are discussed.

Sun Jizhong; Li Xiantao; Sang Chaofeng; Jiang Wei; Zhang Pengyun; Wang Dezhen [School of Physics and Optoelectronic Engineering and College of Advanced Science and Technology, Dalian University of Technology, Dalian 116024 (China)

2010-10-15T23:59:59.000Z

178

Dynamic model of the radio-frequency plasma sheath in a highly asymmetric discharge cell  

Science Journals Connector (OSTI)

A self-consistent fluid model for the radio-frequency sheath at the powered electrode of a highly asymmetric discharge cell is developed and solved. The model assumes time-independent ion motion and inertialess electrons. The voltage on the powered electrode, assumed to be sinusoidal, is shared between the powered sheath and a series resistance that represents the remainder of the discharge. The model includes ion collisions, sheath conduction currents, and secondary electron emission from the electrode surface. Model results are compared with previous sheath models and with experiment. Current wave forms predicted by the model closely resemble the nonsinusoidal current wave forms measured in highly asymmetric cells. The model accurately predicts the shape of sheath voltage wave forms, but not their dc components. The magnitudes and phases of sheath impedances predicted by the model agree with experimental measurements performed in argon discharges at pressures of 4.0–133 Pa.

M. A. Sobolewski

1997-07-01T23:59:59.000Z

179

The parameters of electron cyclotron resonance/radio-frequency hybrid hydrogen plasma adjusted by substrate arrangements  

SciTech Connect (OSTI)

Hybrid hydrogen plasma was formed by biasing 13.56 MHz radio-frequency (rf) power on a substrate immersed in 2.45 GHz microwave electron cyclotron resonance (ECR) plasma. The influences of the substrate configuration on plasma characteristics were investigated. With increasing rf self-bias voltage, electron temperature, T{sub e}, increases obviously in the case of the single-electrode substrate, whereas a slight change in T{sub e} was observed with the double-electrode substrate condition. Electron density rises almost with a same magnitude under both two substrate conditions. It exhibited that electron energy and density in ECR-rf hybrid mode could be adjusted independently by controlling rf discharge with favorable substrate configurations.

Zhou, H. Y.; Wang, L.; Zhu, X. D.; Ke, B.; Ding, F.; Wen, X. H. [CAS Key Laboratory of Basic Plasma Physics, Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Wang, Y. N. [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116023 (China)

2010-03-15T23:59:59.000Z

180

Resonance Cone Interaction With a Self-Consistent Radio-Frequency Sheath  

Science Journals Connector (OSTI)

We study the propagation of lower-hybrid-type resonance cones in a tenuous magnetized plasma, and, in particular, their interaction with, and reflection from, the plasma sheath near a conducting wall. The sheath is modeled as a vacuum gap whose width is given by the Child-Langmuir law. The application of interest is when the resonance cones are launched (parasitically) by an ion-cyclotron radio-frequency antenna in a typical rf-heated tokamak fusion experiment. We calculate the fraction of launched voltage in the resonance cones that is transmitted to the sheath, and show that it has a sensitive thresholdlike turn on when a critical parameter reaches order unity. Above threshold, the fractional voltage transmitted to the sheath is order unity, leading to strong and potentially deleterious rf-wall interactions in tokamak rf heating experiments. Below threshold, these interactions can be avoided.

J. R. Myra and D. A. D’Ippolito

2008-11-06T23:59:59.000Z

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

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

182

LOW-FREQUENCY OBSERVATIONS OF TRANSIENT QUASI-PERIODIC RADIO EMISSION FROM THE SOLAR ATMOSPHERE  

SciTech Connect (OSTI)

We report low-frequency observations of quasi-periodic, circularly polarized, harmonic type III radio bursts whose associated sunspot active regions were located close to the solar limb. The measured periodicity of the bursts at 80 MHz was ?5.2 s, and their average degree of circular polarization (dcp) was ?0.12. We calculated the associated magnetic field B (1) using the empirical relationship between the dcp and B for the harmonic type III emission, and (2) from the observed quasi-periodicity of the bursts. Both the methods result in B ? 4.2 G at the location of the 80 MHz plasma level (radial distance r ? 1.3 R{sub ?}) in the active region corona.

Sasikumar Raja, K.; Ramesh, R., E-mail: sasikumar@iiap.res.in [Indian Institute of Astrophysics, II Block, Koramangala, Bangalore 560 034 (India)

2013-09-20T23:59:59.000Z

183

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

184

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

185

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

186

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

187

Effect of excitation frequency on source characteristics in radio frequency glow discharge atomic emission spectrometry-I. 2–30 \\{MHz\\}  

Science Journals Connector (OSTI)

The role of excitation frequency on the electrical, atomization, and optical emission characteristics of a radio frequency glow discharge atomic emission (rf-GD-AES) source was investigated in the frequency range of 2–30 MHz. Comparisons between the applied (peak-to-peak) potentials and the resultant dc bias potentials indicate that the discharge energy is dissipated more at the sample surface at lower frequencies and in the negative glow region in the upper frequency range. As a result, sputtering rates are greatest at the lowest frequency (2 MHz). The response of a variety of Cu I and II emission transitions to changes in frequency illustrates the need to choose separately the analytical transitions at a given frequency. In general, however, high-lying transitions optimize at low frequencies, with resonant transitions showing enhancements at high ones. As such, the operating frequency has a somewhat diametric effect on atomization and excitation characteristics. Finally, analytical figures of merit are illustrated for a number of analytes and transitions in a copper standard. While differences exist in the response of line intensity to operating frequency, background levels decrease and stability of the plasma improves with increased frequency.

Chris Lazik; R.Kenneth Marcus

1994-01-01T23:59:59.000Z

188

Argon metastable densities in radio frequency Ar, Ar/O2 and Ar/CF4 electrical discharges  

E-Print Network [OSTI]

Argon metastable densities in radio frequency Ar, Ar/O2 and Ar/CF4 electrical discharges Shahid. In this article, we present results from a two-dimensional computer simulation of Ar, Ar/O2, and Ar/CF4 discharges in the ambipolar electric field resulting from electrode structures. Additions of small amounts of O2 and CF4

Kushner, Mark

189

Sheet resistance of LiNbO3 wafers processed in radio-frequency plasma of hydrogen  

Science Journals Connector (OSTI)

Radio-frequency discharge of 13.56MHz in hydrogen was...3...wafers under an electrodeless capacitive coupling. At a pressure of 0.5 torr and RF input power of 250 W a surface...3...wafers was created in which the...

H. Tur?i?ová; J. Pracha?ová; J. ?ervená; J. Vacík

2000-03-01T23:59:59.000Z

190

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

191

Chapter 1.6.7 - Biological Effects of Radio-Frequency Fields  

Science Journals Connector (OSTI)

Publisher Summary This chapter discusses the biological effect of radio-frequency (rf) fields. It has initiated many investigations on biological effects of low-level electromagnetic fields. The aim of the chapter is to present a critical review of the current knowledge of the effects of rf fields on biological systems and to introduce various setups designed to test the influence of rf fields on these systems especially for the mobile communication frequency range (200 \\{MHz\\} to 2.5 GHz). In experiments whose aim is to test the effects of rf fields on technical or biological systems, the design of the exposure setup is a very important step. Insufficient knowledge of the field distribution inside the specimen will lead to wrong results. Independent of the outcome itself, wrong positive as well as wrong negative results may be the consequence and the experimental work and the money invested will be wasted. Testing the effects of rf fields on biological systems needs both detailed knowledge about the actual field distribution inside the specimen and well-documented reliable biological processes whose potential changes may finally be put down to the presence of an rf field.

R. Meyer; J. Streckert; V. Hansen

2002-01-01T23:59:59.000Z

192

Capacitively coupled radio-frequency hydrogen discharges: The role of kinetics  

SciTech Connect (OSTI)

This paper presents a systematic characterization of capacitively coupled radio-frequency hydrogen discharges, produced within a parallel plate cylindrical setup at different rf applied voltages (V{sub rf}=50-600 V), frequencies (f=13.56-40.68 MHz), and pressures (p=0.2-1 torr). A two-dimensional, time-dependent fluid model for charged particle transport is self-consistently solved coupled to a homogeneous kinetic model for hydrogen, including vibrationally excited molecular species and electronically excited atomic species. Numerical simulations are compared with experimental measurements of various plasma parameters. A good quantitative agreement is found between simulations and experiment for the coupled electrical power and the plasma potential. The model underestimates the values of the electron density, the self-bias potential, and the H(n=1) atom density with respect to measurements, but agrees with experiment when predicting that all these parameters increase with either V{sub rf}, f, or p. The dissociation degree is about 10{sup -3} for the work conditions considered. Simulations adopt a wall recombination probability for H atoms that was experimentally measured, thus accounting for surface modification with discharge operating conditions. Results show the key role played by the atomic wall recombination mechanism in plasma description.

Marques, L.; Jolly, J.; Alves, L. L. [Departamento de Fisica, Universidade do Minho, 4710-057 Braga (Portugal); Laboratoire de Physique et Technologie des Plasmas, Ecole Polytechnique, 91128 Palaiseau Cedex (France); Centro de Fisica dos Plasmas, Instituto Superior Tecnico, 1049-001 Lisboa (Portugal)

2007-09-15T23:59:59.000Z

193

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

194

Effects of Scattering on Radio Emission from the Quiet Sun at Low Frequencies  

Science Journals Connector (OSTI)

The observations of the quiet Sun at meter and decameter wavelengths show that its brightness temperatures can be ~1 order of magnitude lower than the expected values of 106 K and the apparent diameters can be very large. We examine whether this unusual behavior is due to refraction in the smoothly varying coronal plasma and scattering by random density fluctuations using an improved Monte Carlo simulation technique. We use a three-dimensional model for the electron density, -->Ne, and a power-law spectrum for the density fluctuations with an exponential index of ?. We consider two cases: (1) -->? = 11/3 (Kolmogorov spectrum), relative level of density fluctuations --> = ? Ne/Ne = 0.1, and scale heights ranging from the inner scale -->li = 684(Ne cm ?3)?1/2 to outer scale -->lo = 106li, and (2) -->? = 3 (flat spectrum), --> = 0.02, and scale heights ranging from 50 to 75 km. We consider the fluctuations to be anisotropic with axial ratios of ~10. The Kolmogorov type of fluctuations yield slightly lower brightness temperatures in comparison with those of a flat spectrum. The brightness temperature distributions, east-west diameters, and central brightness temperatures at various frequencies indicate that the refraction and scattering are probably the underlying reasons for the unusual behavior of the quiet-Sun radio emission. This study clearly demonstrates that Monte Carlo techniques can be very effective in extracting the coronal electron temperatures accurately from the radio data, provided the information about the density distributions and density fluctuations is known by some independent methods.

G. Thejappa; R. J. MacDowall

2008-01-01T23:59:59.000Z

195

Focused excimer laser initiated, radio frequency sustained high pressure air plasmas  

SciTech Connect (OSTI)

Measurements and analysis of air breakdown processes and plasma production by focusing 193 nm, 300 mJ, 15 MW high power laser radiation inside a 6 cm diameter helical radio frequency (RF) coil are presented. Quantum resonant multi-photon ionization (REMPI) and collisional cascade laser ionization processes are exploited that have been shown to produce high-density (n{sub e} {approx} 7 x 10{sup 16}/cm{sup 3}) cylindrical seed plasmas at 760 Torr. Air breakdown in lower pressures (from 7-22 Torr), where REMPI is the dominant laser ionization process, is investigated using an UV 18 cm focal length lens, resulting in a laser flux of 5.5 GW/cm{sup 2} at the focal spot. The focused laser power absorption and associated shock wave produce seed plasmas for sustainment by the RF (5 kW incident power, 1.5 s) pulse. Measurements of the helical RF antenna load impedance in the inductive and capacitive coupling regimes are obtained by measuring the loaded antenna reflection coefficient. A 105 GHz interferometer is used to measure the plasma electron density and collision frequency. Spectroscopic measurements of the plasma and comparison with the SPECAIR code are made to determine translational, rotational, and vibrational neutral temperatures and the associated neutral gas temperature. From this and the associated measurement of the gas pressure the electron temperature is obtained. Experiments show that the laser-formed seed plasma allows RF sustainment at higher initial air pressures (up to 22 Torr) than that obtained via RF-only initiation (<18 Torr) by means of a 0.3 J UV laser pulse.

Giar, Ryan; Scharer, John [Department of Electrical Engineering, University of Wisconsin-Madison, 506 Engineering Research Building, 1500 Engineering Drive, Madison, Wisconsin 53706 (United States)

2011-11-15T23:59:59.000Z

196

Deposition of vertically oriented carbon nanofibers in atmospheric pressure radio frequency discharge  

SciTech Connect (OSTI)

Deposition of vertically oriented carbon nanofibers (CNFs) has been studied in an atmospheric pressure radio frequency discharge without dielectric barrier covering the metallic electrodes. When the frequency is sufficiently high so that ions reside in the gap for more than one rf cycle ('trapped ions'), the operating voltage decreases remarkably and the transition from a uniform glow discharge to an arc discharge is suppressed even without dielectric barriers. More importantly, the trapped ions are able to build up a cathodic ion sheath. A large potential drop is created in the sheath between the bulk plasma and the electrode, which is essential for aligning growing CNFs. At the same time, the damage to CNFs due to ion bombardment can be minimized at atmospheric pressure. The primary interest of the present work is in identifying the cathodic ion sheath and investigating how it influences the alignment of growing CNFs in atmospheric pressure plasma-enhanced chemical-vapor deposition. Spectral emission profiles of He (706 nm), H{alpha} (656 nm), and CH (432 nm) clearly showed that a dark space is formed between the cathode layer and the heated bottom electrode. However, increasing the rf power induced the transition to a nonuniform {gamma}-mode discharge which creates intense plasma spots in the dark space. Aligned CNFs can be grown at moderate input power during the initial stage of the deposition process. Catalyst particles were heavily contaminated by precipitated carbon in less than 5 min. Alignment deteriorates as CNFs grow and deposition was virtually terminated by the deactivation of catalyst particles.

Nozaki, Tomohiro; Goto, Tomoya; Okazaki, Ken; Ohnishi, Kuma; Mangolini, Lorenzo; Heberlein, Joachim; Kortshagen, Uwe [Department of Mechanical and Control Engineering, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro Tokyo 1528552 (Japan); Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

2006-01-15T23:59:59.000Z

197

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

198

Instabilities and multiple steady states of radio-frequency discharges in CF4  

Science Journals Connector (OSTI)

A one-dimensional fluid model coupled with solution tracking algorithms was applied for an L=5 mm CF4 (radio frequency) rf discharge at P=2 Torr (low PL value of PL=1). The discharge exhibited a rich behavior of solution multiplicity as a function of applied rf current density (or voltage). The most prominent characteristic was the development of dc self-bias and asymmetry under completely symmetric discharge conditions, in agreement with experimental data by J. Butterbaugh (Ph.D. dissertation, Massachusetts Institute of Technology, 1990). The plasma can exist in three states of positive, negative, and zero self-bias, of which the first two are asymmetric and stable, while the third is symmetric and unstable. The two asymmetric solutions collapse again into one symmetric solution with zero self-bias at a higher voltage, a transition which depends on the value of the secondary electron emission coefficient. At lower applied currents (or voltages) the hysterisis loop of this electronegative plasma is presented between breakdown and extinction, and an unstable plasma is found between the two points. The observed phenomena are related to the transition of the discharge from diffusion-controlled to electron-oscillation-amplitude-controlled breakdowns. The sustaining mechanisms of the plasma and the electron dynamics are discussed. © 1996 The American Physical Society.

Efimia Metsi; Evangelos Gogolides; Andreas Boudouvis

1996-07-01T23:59:59.000Z

199

Production of oxygen plasmas using radio-frequency magnetron-discharge  

Science Journals Connector (OSTI)

A new type of oxygen ion source has been developed in order to substantially prolong the lifetime of a conventional oxygen ion source for various plasma processes. In this ion source, an oxygen plasma is produced by coupling a 13.56 \\{MHz\\} radio-frequency (rf) field to a pair of rf electrodes placed in the region of a line cusp field. Two electrodes are positioned in such a way that accelerated electrons undergo magnetron type motion around them, efficiently producing a plasma around the electrodes (rf magnetron discharge). This plasma diffuses along the magnetic field line into the center region of the cusp field where the field strength is almost nil. The above process makes it possible to produce a large volume of uniform plasma. As a result, extraction of a large area oxygen-ion-beam from the new ion source is relatively easy. The lifetime of this ion source is virtually limitless, because it does not have any corrosive parts, such as a hot filament. The new ion source can be used with any kind of reactive gases as well as oxygen.

Takehisa Shibuya; Shizuyo Hashimoto; Eiji Yabe; Kazuo Takayama

1991-01-01T23:59:59.000Z

200

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

Note: This page contains sample records for the topic "radio frequency identification" from the National Library of EnergyBeta (NLEBeta).
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201

Control of radio-frequency atmospheric pressure argon plasma characteristics by helium gas mixing  

SciTech Connect (OSTI)

The control of plasma characteristics is one of the important issues in many atmospheric pressure plasma applications. In order to accomplish this control, a feasibility study was performed by investigating the role of helium gas in an argon glow plasma that were produced in ambient air by 13.56 MHz radio-frequency power. Optical emission spectroscopy was used to measure rotational temperature and emission spectra acquired between 300 and 840 nm. Based on electrical and optical measurements, parameters such as gas temperature, breakdown voltage, power coupling efficiency, spatial uniformity of rotational temperature, and the sum of the emission intensity were controlled by varying the argon and helium gas mixing ratio. The addition of helium gas (from 0 to 10 lpm) to the argon flow (of 10 lpm) lowered the breakdown voltage (from 430 to 300 V{sub pk}) and the rotational temperature (from 465 to 360 K). However, an excessive addition of helium resulted in a reduction of the spatial uniformity and efficiency of power coupling. When the ratio of helium to argon flow was between 0.3 and 0.5, a high spatial uniformity with a relatively low gas temperature and breakdown voltage was achieved. This suggests that mixing of the supply gas is a useful way of controlling the plasma characteristics that may be utilized for applications with specific required discharge conditions.

Moon, Se Youn; Han, Jewoo; Choe, W. [Department of Physics, Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

2006-01-15T23:59:59.000Z

202

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

203

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

204

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

205

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

206

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

207

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 [Unità 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

208

H{sup -} beam extraction from a cesium seeded field effect transistor based radio frequency negative hydrogen ion source  

SciTech Connect (OSTI)

H{sup -} beam was successfully extracted from a cesium seeded ion source operated using a field effect transistor inverter power supply as a radio frequency (RF) wave source. High density hydrogen plasma more than 10{sup 19} m{sup -3} was obtained using an external type antenna with RF frequency of lower than 0.5 MHz. The source was isolated by an isolation transformer and H{sup -} ion beam was extracted from a single aperture. Acceleration current and extraction current increased with the increase of extraction voltage. Addition of a small amount of cesium vapor into the source enhanced the currents.

Ando, A.; Matsuno, T.; Funaoi, T.; Tanaka, N. [School of Engineering, Tohoku University, Sendai 980-8579 (Japan); Tsumori, K.; Takeiri, Y. [National Institute for Fusion Science, Toki 509-5292 (Japan)

2012-02-15T23:59:59.000Z

209

H{sup -} radio frequency source development at the Spallation Neutron Source  

SciTech Connect (OSTI)

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

Welton, R. F.; Gawne, K. R.; Han, B. X.; Murray, S. N.; Pennisi, T. R.; Roseberry, R. T.; Santana, M.; Stockli, M. P. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37830-6471 (United States); Dudnikov, V. G. [Muons, Inc., 552 N. Batavia Avenue, Batavia, Illinois 60510 (United States); Turvey, M. W. [Villanova University, 800E. Lancaster Ave, Villanova, Pennsylvania 19085 (United States)

2012-02-15T23:59:59.000Z

210

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

211

One-Dimensional Modeling on the Asymmetric Features of a Radio-Frequency Atmospheric Helium Glow Discharge Produced Using a Co-Axial-Type Plasma Generator  

Science Journals Connector (OSTI)

As one type of the atmospheric glow discharges, the radio-frequency atmospheric-pressure glow discharges produced using the water-cooled bare-metallic electrode, which are the...1–3...]. The capacitively-coupled ...

Zhi-Bin Wang; Pei-Si Le; Nan Ge; Qiu-Yue Nie…

2012-08-01T23:59:59.000Z

212

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

213

Heating of Plasma Ions in a Tokamak by the Second-Harmonic Ion-Cyclotron Resonance Interaction with Radio-Frequency Waves  

Science Journals Connector (OSTI)

The radio-frequency-wave heating of ions in a tokamak plasma employing the second-harmonic ion-cyclotron resonance interaction has been demonstrated in recent high-power (3-MW) experiments on the Princeton Large Torus tokamak.

D. Q. Hwang; J. Hosea; H. Thompson; J. R. Wilson; S. Davis; D. Herndon; R. Kaita; D. Mueller; S. Suckewer; C. Daughney; P. Colestock

1983-11-14T23:59:59.000Z

214

Room-temperature high radio-frequency source power effects on silicon nitride films deposited by using a plasma-enhanced chemical vapor deposition  

Science Journals Connector (OSTI)

Silicon nitride films were deposited at room temperature using a plasma-enhanced chemical vapor deposition system. In this study, the effects of radio frequency (RF) source power ranging from 200 W to ... charact...

Byungwhan Kim; Suyeon Kim

2008-10-01T23:59:59.000Z

215

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

216

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

217

Comparative study of laminar and turbulent flow model with different operating parameters for radio frequency-inductively coupled plasma torch working at 3??MHz frequency at atmospheric pressure  

Science Journals Connector (OSTI)

This paper provides 2D comparative study of results obtained using laminar and turbulent flow model for RF (radio frequency) Inductively Coupled Plasma (ICP) torch. The study was done for the RF-ICP torch operating at 50?kW DC power and 3?MHz frequency located at BARC. The numerical modeling for this RF-ICP torch is done using ANSYS software with the developed User Defined Function. A comparative study is done between laminar and turbulent flow model to investigate how temperature and flow fields change when using different operating conditions such as (a) swirl and no swirl velocity for sheath gas flow rate (b) variation in sheath gas flow rate and (c) variation in plasma gas flow rate. These studies will be useful for different material processing applications.

Sangeeta B. Punjabi; S. N. Sahasrabudhe; N. K. Joshi; H. A. Mangalvedekar; A. K. Das; D. C. Kothari

2014-01-01T23:59:59.000Z

218

Radio frequency dc-dc converters : device characterization, topology evaluation, and design  

E-Print Network [OSTI]

High frequency power conversion is attractive for the opportunities it affords for improved performance. Dc-dc converters operating at high frequencies use smaller-valued energy storage elements, which tend to be physically ...

Leitermann, Olivia

2008-01-01T23:59:59.000Z

219

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

220

Limits on low-frequency radio emission from southern exoplanets with the Murchison Widefield Array  

Science Journals Connector (OSTI)

......Zealand 16 Department of Atmospheric, Oceanic and Space Sciences...radio emission at 154-MHz, and put 3sigma upper...would give a limit on the plasma density in the magnetosphere...VLA) at 333 and 1400-MHz, but made no detections...VLA at 333 and 1465-MHz and one at 74-MHz......

Tara Murphy; Martin E. Bell; David L. Kaplan; B. M. Gaensler; André R. Offringa; Emil Lenc; Natasha Hurley-Walker; G. Bernardi; J. D. Bowman; F. Briggs; R. J. Cappallo; B. E. Corey; A. A. Deshpande; D. Emrich; R. Goeke; L. J. Greenhill; B. J. Hazelton; J. N. Hewitt; M. Johnston-Hollitt; J. C. Kasper; E. Kratzenberg; C. J. Lonsdale; M. J. Lynch; S. R. McWhirter; D. A. Mitchell; M. F. Morales; E. Morgan; D. Oberoi; S. M. Ord; T. Prabu; A. E. E. Rogers; D. A. Roshi; N. Udaya Shankar; K. S. Srivani; R. Subrahmanyan; S. J. Tingay; M. Waterson; R. B. Wayth; R. L. Webster; A. R. Whitney; A. Williams; C. L. Williams

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.


221

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

222

Radio-frequency measurements of UNiX compounds (X= Al, Ga, Ge) in high magnetic fields  

SciTech Connect (OSTI)

We performed radio-frequency (RF) skin-depth measurements of antiferromagnetic UNiX compounds (X=Al, Ga, Ge) in magnetic fields up to 60 T and at temperatures between 1.4 to {approx}60 K. Magnetic fields are applied along different crystallographic directions and RF penetration-depth was measured using a tunnel-diode oscillator (TDO) circuit. The sample is coupled to the inductive element of a TDO resonant tank circuit, and the shift in the resonant frequency {Delta}f of the circuit is measured. The UNiX compounds exhibit field-induced magnetic transitions at low temperatures, and those transitions are accompanied by a drastic change in {Delta}f. The results of our skin-depth measurements were compared with previously published B-T phase diagrams for these three compounds.

Mielke, Charles H [Los Alamos National Laboratory; Mcdonald, David R [Los Alamos National Laboratory; Zapf, Vivien [Los Alamos National Laboratory; Altarawneh, Moaz M [Los Alamos National Laboratory; Lacerda, Alex H [Los Alamos National Laboratory; Adak, Sourav [Los Alamos National Laboratory; Karunakar, Kothapalli [Los Alamos National Laboratory; Nakotte, Heinrich [Los Alamos National Laboratory; Chang, S [NIST; Alsmadi, A M [HASHEMITE UNIV; Alyones, S [HASHEMIT UNIV

2009-01-01T23:59:59.000Z

223

Quasi-simultaneous observations of BL Lac object Mrk 501 in X-ray, UV, visible, IR, and radio frequencies  

SciTech Connect (OSTI)

Quasi-simultaneous observations of the BL Lac object Mrk 501 were performed for the first time at X-ray, ultraviolet, visible infrared, and radio frequencies. As the BL Lac objects are known to vary in their flux, such a ''quasi-instantaneous'' spectral energy profile is necessary in order to describe properly the energy generation mechanism. The observed spectral slope from the X-ray to UV regions is positive and continuous, but that from the mid-UV to visible light region becomes gradually flat and possibly turns down toward lower frequencies; the optical-radio emission cannot be accounted for by a single power law. Several theoretical models have been considered for the emission mechanism. In some cases quantitative comparison with the data is not practical. However, most of the models are, at least, not inconsistent with the observations. A quantitative comparison has been peformed with the synchroton self-Compton model; the total spectrum is found consistent with this model. The spectrum from visible light to X-ray is consistent with synchrotron radiation or with inverse-Compton scattering by a hot thermal cloud of electrons. The continuity of the spectral slope from X-ray to UV implied by the current data suggests that the previous estimates of the total luminosity of this BL Lac object has been underestimated by a factor of about 3 or 4.

Kondo, Y.; Worrall, D.M.; Mushotzky, R.F.; Hackney, R.L.; Hackney, K.R.H.; Oke, J.B.; Yee, H.K.C.; Neugebauer, G.; Matthews, K.; Feldman, P.A.; Brown, R.L.

1981-02-01T23:59:59.000Z

224

GEOPHYSICAL RESEARCH LETTERS, VOL. ???, XXXX, DOI:10.1029/, Detecting nanoparticles at radio frequencies: Jovian  

E-Print Network [OSTI]

T December 26, 2008, 4:59pm D R A F T #12;X - 2 MEYER-VERNET ET AL.: DETECTING NANOPARTICLES AT RADIO with a conventional detection by a dust analyser attributed to nanoparticles. D R A F T December 26, 2008, 4:59pm D R dust detectors: first it has a D R A F T December 26, 2008, 4:59pm D R A F T #12;X - 4 MEYER-VERNET ET

Demoulin, Pascal

225

Radio-Frequency Interference (RFI) From Extra-High-Voltage (EHV) Transmission Lines  

E-Print Network [OSTI]

discharges are a design issue. Extra-high-voltage (EHV) transmission lines have operating voltages of 345 kV building a 345-kV transmission line from Red Hill, NM to Deming, NM which would run east along US60 to its with respect to radio noise: (1) lines with voltages below 70 kV and (2) lines with voltages above 110 kV

Ellingson, Steven W.

226

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

227

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

E-Print Network [OSTI]

identifying and verifying agrochemicals in food traceabilitytreatment specifics (agrochemicals and dates of treatment),ing and application of agrochemicals and Database links

Luvisi, Andrea; Panattoni, Alessandra; Triolo, Enrico

2012-01-01T23:59:59.000Z

228

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

SciTech Connect (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 Booetes field. These 76 sources were selected from the FIRST catalog to have peak flux densities above 10 mJy at 5'' resolution and deconvolved major diameters of less than 3'' at 1.4 GHz. Fifty-five 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 possibilities arising from source-resolution effects. Thirty of the faint radio sources, or 39{sub -7}{sup +9}%, were detected with the VLBA at 5.0 GHz with peak flux densities above 6 {sigma} {approx} 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 corresponds 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. Eight 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.

Wrobel, J.M.; /NRAO, Socorro; Taylor, Greg B.; /NRAO, Socorro /KIPAC, Menlo Park; Rector, T.A.; /NRAO, Socorro /Alaska U.; Myers, S.T.; /NRAO, Socorro; Fassnacht, C.D.; /UC,

2005-06-13T23:59:59.000Z

229

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

230

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

231

A HIGH-FREQUENCY TYPE II SOLAR RADIO BURST ASSOCIATED WITH THE 2011 FEBRUARY 13 CORONAL MASS EJECTION  

SciTech Connect (OSTI)

We examine the relationship between the high-frequency (425 MHz) type II radio burst and the associated white-light coronal mass ejection (CME) that occurred on 2011 February 13. The radio burst had a drift rate of 2.5 MHz s{sup -1}, indicating a relatively high shock speed. From SDO/AIA observations we find that a loop-like erupting front sweeps across high-density coronal loops near the start time of the burst (17:34:17 UT). The deduced distance of shock formation (0.06 Rs) from the flare center and speed of the shock (1100 km s{sup -1}) using the measured density from SDO/AIA observations are comparable to the height (0.05 Rs, from the solar surface) and speed (700 km s{sup -1}) of the CME leading edge observed by STEREO/EUVI. We conclude that the type II burst originates even in the low corona (<59 Mm or 0.08 Rs, above the solar surface) due to the fast CME shock passing through high-density loops.

Cho, K.-S.; Kim, R.-S. [Korea Astronomy and Space Science Institute, Whaamdong, Yooseong-ku, Daejeon, 305-348 (Korea, Republic of); Gopalswamy, N.; Kwon, R.-Y.; Yashiro, S., E-mail: kscho@kasi.re.kr [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

2013-03-10T23:59:59.000Z

232

Advanced Heat Transfer Studies in Superfluid Helium for Large-scale High-yield Production of Superconducting Radio Frequency Cavities  

E-Print Network [OSTI]

Oscillating Superleak Transducers (OSTs) can be used to localize quenches in superconducting radio frequency cavities. In the presented work the occurring thermal effects during such events are investigated both theoretically and experimentally. In the theoretical part the entire heat transfer process from the heat generation to the detection is covered. The experimental part focuses on the effects in superfluid helium. Previous publications observed the detection of an OST signal that was faster than the second sound velocity. This fast propagation could be verified in dedicated small scale experiments. Resistors were used to simulate the quench spots under controlled conditions. The three dimensional propagation of second sound was linked to OST signals for the first time, which improves the understanding of the OST signal and allows to gather information about the heating pulse. Additionally, OSTs were used as a tool for quench localisation on a real size cavity. Their sensitivity as well as the time resol...

Peters, Benedikt J; Schirm, Karl-Martin; Koettig, Torsten

233

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

234

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

235

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

236

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

237

Gas breakdown in an atmospheric pressure radio-frequency capacitive plasma source  

Science Journals Connector (OSTI)

Gas breakdown is studied in an atmospheric pressure rf capacitive plasma source developed for materials applications. At a rf frequency of 13.56 MHz breakdown voltage is largely a function of the product of the pressure and the discharge gap spacing approximating the Paschen curve. However breakdown voltage varies substantially with rf frequency due to a change in the electron loss mechanism. A large increase in breakdown voltage is observed when argon oxygen or nitrogen is added to helium despite their lower ionization potential. Discussion is given for optimal breakdown conditions at atmospheric pressure.

Jaeyoung Park; I. Henins; H. W. Herrmann; G. S. Selwyn

2001-01-01T23:59:59.000Z

238

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

239

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

240

Radio-frequency integrated-circuit design for CMOS single-chip UWB systems  

E-Print Network [OSTI]

switch utilizes the synthetic transmission line concept and multiple reflections technique in order to realize a flat insertion loss less than 1.5 dB from 3.1 GHz to 10.6 GHz and an extremely high isolation of more than 45 dB within this frequency range...

Jin, Yalin

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.


241

Direct measurement of density oscillation induced by a radio-frequency wave  

SciTech Connect (OSTI)

An O-mode reflectometer at a frequency of 25.85 GHz was applied to plasmas heated by the high harmonic fast wave (21 MHz) in the TST-2 spherical tokamak. An oscillation in the phase of the reflected microwave in the rf range was observed directly for the first time. In TST-2, the rf (250 kW) induced density oscillation depends mainly on the poloidal rf electric field, which is estimated to be about 0.2 kV/m rms by the reflectometer measurement. Sideband peaks separated in frequency by ion cyclotron harmonics from 21 MHz, and peaks at ion cyclotron harmonics which are suggested to be quasimodes generated by parametric decay, were detected.

Yamada, T.; Ejiri, A.; Shimada, Y.; Oosako, T.; Tsujimura, J.; Takase, Y.; Kasahara, H. [Research Institute for Applied Mechanics, Kyushu University, Kasuga 816-8580 (Japan); Graduate School of Frontier Sciences, University of Tokyo, Kashiwa 277-8561 (Japan); National Institute for Fusion Science, Toki 509-5292 (Japan)

2007-08-15T23:59:59.000Z

242

Survey paper: A survey of applications and requirements of unique identification systems and RFID techniques  

Science Journals Connector (OSTI)

The paper contains an overview of unique identification issues and of the various radio frequency identification techniques that are available now or will become available in the short term. The paper also compares RFID with traditional ID technologies. ... Keywords: Automatic identification, Data transfer, Identifier-based operations, Supply-chain

Elisabeth Ilie-Zudor; Zsolt Kemény; Fred van Blommestein; László Monostori; André van der Meulen

2011-04-01T23:59:59.000Z

243

Two-dimensional laser-induced fluorescence imaging of metastable density in low-pressure radio frequency argon plasmas with added O2, Cl2,  

E-Print Network [OSTI]

frequency argon plasmas with added O2, Cl2, and CF4 Brian K. McMillina) and M. R. Zachariah Chemical Science, and CF4 on the argon metastable relative density and spatial distribution in low-pressure, radio at the powered electrode. In contrast, the addition of either Cl2 or CF4 was found to significantly modify

Zachariah, Michael R.

244

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

245

Compression effects in inductively coupled, high-power radio-frequency discharges for negative hydrogen ion production  

Science Journals Connector (OSTI)

In the paper we present a simplified model description of inductively coupled plasmadischarges operating at a rather high radio-frequency (rf) power. In this case the induced high plasma currents can cause periodic compressions over a substantial radial distance. Such conditions are obviously given in rf driven 1 MHz/150 kW plasma sources developed at the Institute for Plasma Physics Garching for negative (hydrogen) ion production in future neutral beam injection (NBI) systems for nuclear fusion research such as the 1 MeV/50 MW NBI system for the International Thermonuclear Experimental Reactor [T. Inoue R. Hemsworth V. Kulygin and Y. Okumura Fusion Eng. Design 55 291 (2001)]. The given model describes quite well the compression and other features of the discharge. The results include the Ohmic power input (i.e. electron heating) the resulting density build-up and—as a new feature—periodical plasma compressions leading to a direct energy input also into the plasma ions. The model also explains the strange effect of small argon admixtures which improve the negative ion yield in rf sources by a factor of up to 2–3 (but which have no effect in conventional dc arc sources). With the calculated dependencies from external parameters (e.g. rf-power and frequency gas pressure ion mass or the specific geometry) the modeling may help for the further optimization of the rf source.

Rolf Wilhelm

2003-01-01T23:59:59.000Z

246

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

247

Dust removal in radio-frequency plasmas by a traveling potential modulation  

SciTech Connect (OSTI)

The dust contamination in plasma deposition processes plays a crucial role in the quality and the yield of the products. To improve the quality and the yield of plasma processing, a favorable way is to remove the dust particles actively from the plasma reactors.Our recent experiments in the striped electrode device show that a traveling plasma modulation allows for a systematic particle removal independent of the reactor size. Besides the rf powered electrode, the striped electrode device includes a segmented electrode that consists of 100 electrically insulated narrow stripes. A traveling potential profile is produced by the modulation of the voltage signals applied on the stripes. The dust particles are trapped in the potential wells and transported with the traveling of the potential profile.The particle-in-cell (PIC) simulation on the potential above the segmented electrode indicates that the traveling potential profile can be realized either by applying low-frequency (0.1-10 Hz) voltage signals with a fixed phase shift between adjacent stripes or high-frequency (10 kHz a circumflex AS 100 MHz) signals with the amplitudes modulated by a low-frequency envelope. The transportation of the dust particles is simulated with a two-dimensional molecular dynamics (MD) code with the potential profile obtained from the PIC simulation. The MD results reproduce the experimental observations successfully.This technology allows for an active removal of the contaminating particles in processing plasmas and it is independent of the reactor size. The removal velocity is controllable by adjusting the parameters for the modulation.

Li Yangfang; Jiang Ke; Thomas, Hubertus M.; Morfill, Gregor E. [Max-Planck-Institute for Extraterrestrial Physics, 85748 Garching (Germany)

2010-06-16T23:59:59.000Z

248

Experimental observation of delay-induced radio frequency chaos in a transmission line oscillator  

Science Journals Connector (OSTI)

We report an experimental study of fast chaotic dynamics in a delay dynamical system. The system is an electronic device consisting of a length of coaxial cable terminated on one end with a diode and on the other with a negative resistor. When the negative resistance is large the system evolves to a steady state. As the negative resistance is decreased a Hopf bifurcation occurs. By varying the length of the transmission line we observe Hopf frequencies from 7–53? MHz . With the transmission line length fixed we observe a period doubling route to chaos as the negative resistance is further reduced providing the first experimental confirmation of an existing theoretical model for nonlinear dynamics in transmission line oscillators [Corti et al. IEEE Trans. Circ. Syst. I: Fundam. Theory Appl. 41 730 (1994)]. However other experimental results indicate limitations to this model including an inability to predict the Hopf frequency or to produce realistic continuous wave forms. We extend the model to include finite bandwidth effects present in a real negative resistor. The resulting model is a neutral delay differential equation that provides better agreement with experimental results.

Jonathan N. Blakely; Ned J. Corron

2004-01-01T23:59:59.000Z

249

Outline of Radio Astronomy  

Science Journals Connector (OSTI)

... about when a technique developed for one type of investigation is applied to another. Radio astronomy is an excellent example of this. During the past seven years the use of ... radio stars' which emit strongly in the radio-frequency portion of the spectrum."Radio Astronomy", by A. C. B. Lovell and J. A. Clegg, gives an ...

J. A. RATCLIFFE

1953-07-11T23:59:59.000Z

250

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

251

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

252

Cleaning of inner vacuum surfaces in the Uragan-3M facility by radio-frequency discharges  

SciTech Connect (OSTI)

A method for cleaning vacuum surfaces by a low-temperature (T{sub e} ? 10 eV) relatively dense (n{sub e} ? 10{sup 12} cm{sup ?3}) plasma of an RF discharge was developed and successfully applied at the Uragan-3M torsatron. The convenience of the method is that it can be implemented with the same antenna system and RF generators that are used to produce and heat the plasma in the operating mode and does not require retuning the frequencies of the antennas and RF generators. The RF discharge has a high efficiency from the standpoint of cleaning vacuum surfaces. After performing a series of cleanings by the low-temperature RF discharge plasma (about 20000 pulses), (i) the intensity of the CIII impurity line was substantially reduced, (ii) a quasi-steady operating mode with a duration of up to 50 ms, a plasma density of n{sub e} ? 10{sup 12} cm{sup ?3}, and an electron temperature of up to T{sub e} ? 1 keV was achieved, and (iii) mass spectrometric analysis of the residual gas in the chamber indicated a significant reduction in the impurity content.

Lozin, A. V., E-mail: alexlozin@meta.ua; Moiseenko, V. E.; Grigor’eva, L. I.; Kozulya, M. M.; Kulaga, A. E. [National Science Center Kharkiv Institute of Physics and Technology (Ukraine)] [National Science Center Kharkiv Institute of Physics and Technology (Ukraine); Lysoivan, A. I. [Royal Military Academy, Laboratory for Plasma Physics (Belgium)] [Royal Military Academy, Laboratory for Plasma Physics (Belgium); Mironov, Yu. K.; Pavlichenko, R. O.; Romanov, V. S.; Chernyshenko, V. Ya.; Chechkin, V. V. [National Science Center Kharkiv Institute of Physics and Technology (Ukraine)] [National Science Center Kharkiv Institute of Physics and Technology (Ukraine); Collaboration: Uragan-3M Team

2013-08-15T23:59:59.000Z

253

Experimental test of models of high-plasma-density, radio-frequency sheaths  

Science Journals Connector (OSTI)

Measurements of the rf-bias current and voltage applied to the substrate electrode of a high-density plasma reactor, combined with dc measurements of the ion current at the electrode and capacitive probe measurements of the plasma potential, enabled a rigorous, quantitative test of models of the electrical properties of the sheath adjacent to the electrode. The measurements were performed for argon discharges at 1.33 Pa (10 mTorr), ion current densities of 1.3–13 mA/cm2, rf-bias frequencies of 0.1–10 MHz, and rf-bias voltages from less than 1 to more than 100 V. From the measurements, the current, voltage, impedance, and power of the sheath adjacent to the electrode were determined and were compared to model predictions. The properties of the opposing sheath, adjacent to grounded surfaces, were also determined. The behavior of the two sheaths ranged from nearly symmetric to very asymmetric. Changes in the symmetry are explained by models of the sheath impedance.

Mark A. Sobolewski

1999-01-01T23:59:59.000Z

254

Autocatalytic silver-plating of aluminium radio frequency waveguides with autocatalytic nickel as the undercoat for space applications  

Science Journals Connector (OSTI)

Autocatalytic plating, a technique used for evenly coating contoured items with deep cavities, such as microwave components, irrespective of shape and size of the item to be plated, was used in this work to coat a radio frequency waveguide. In this work, a process sequence was developed for autocatalytic silver plating on aluminum base material with autocatalytic nickel as the undercoat. The thickness of the deposited silver depends on variables like temperature, concentration of silver ions in the electrolyte, and the pH of the solution. The influence of these variables was studied under different process conditions. Silver-coated rectangular plates were subjected to various tests, including a bend test, a heat resistance test, a thermal cycling test, a thermo vacuum test, a solderability test, and a humidity resistance test. Autocatalytic silver-coated RF waveguide WR28 was tested for insertion loss and return loss. Autocatalytic silver-plated rectangular plates and waveguides were found to withstand a simulated space environment.

Sharad Shukla; N Gomathi; Rene George

2014-01-01T23:59:59.000Z

255

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

256

Direct coupling of pulsed radio frequency and pulsed high power in novel pulsed power system for plasma immersion ion implantation  

SciTech Connect (OSTI)

A novel power supply system that directly couples pulsed high voltage (HV) pulses and pulsed 13.56 MHz radio frequency (rf) has been developed for plasma processes. In this system, the sample holder is connected to both the rf generator and HV modulator. The coupling circuit in the hybrid system is composed of individual matching units, low pass filters, and voltage clamping units. This ensures the safe operation of the rf system even when the HV is on. The PSPICE software is utilized to optimize the design of circuits. The system can be operated in two modes. The pulsed rf discharge may serve as either the seed plasma source for glow discharge or high-density plasma source for plasma immersion ion implantation (PIII). The pulsed high-voltage glow discharge is induced when a rf pulse with a short duration or a larger time interval between the rf and HV pulses is used. Conventional PIII can also be achieved. Experiments conducted on the new system confirm steady and safe operation.

Gong Chunzhi; Tian Xiubo; Yang Shiqin [State Key Laboratory of Advanced Welding Production and Technology, School of Materials Science and Engineering, Harbin Institute of Technology, 150001 Harbin (China); Fu, Ricky K. Y.; Chu, Paul K. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong)

2008-04-15T23:59:59.000Z

257

Convective heat and mass transfer and evolution of the moisture distribution in combined convection and radio frequency drying  

SciTech Connect (OSTI)

In a previous study (Dostie and Navarri, 1994), experiments indicated that a non-uniform moisture distribution could develop in radio frequency drying depending on the applied power and initial conditions, making the design and scale-up of such a dryer a more difficult task. Consequently, a thorough study of the combined convection and RF drying process was undertaken. Experimental results have shown that the values of the heat and mass transfer coefficients decrease with an increase in evaporation rate caused by RF energy. This effect is adequately taken into account by the boundary layer theory. Furthermore, the usual analogy between heat and mass transfer has been verified to apply in RF drying. Experiments have also shown that a different mass transfer resistance on both sides of the product should not result in non-uniform drying. However, it appears that non-uniform drying is dependent upon the initial moisture distribution and the relative intensity of heat transfer by convection and RF. It was shown that the maximum drying rate occurs at a higher average water content and that the total drying time increases with non-uniformity of the initial moisture distribution.

Poulin, A.; Dostie, M.; Kendall, J. [LTEE d`Hydro-Quebec, Shawinigan, Quebec (Canada); Proulx, P. [Univ. de Sherbrooke, Quebec (Canada)

1997-10-01T23:59:59.000Z

258

Radio Data  

Science Journals Connector (OSTI)

... abacs provided now cover wave-lengths down to five metres, while provision is made for audio-frequencies over the range 20-10,000 cycles a second. This publication contains a ... the means for obtaining the inductance, capacitance and reactance of coils and condensers at both audio- and radio-frequencies, charts are given for obtaining the efficiency and time constant of ...

1935-12-21T23:59:59.000Z

259

Proposal for the award of a contract for the supply of electronics for the temperature control of cavity windows and helium gas return lines for the superconducting cavities of the LEP200 radio frequency system  

E-Print Network [OSTI]

Proposal for the award of a contract for the supply of electronics for the temperature control of cavity windows and helium gas return lines for the superconducting cavities of the LEP200 radio frequency system

1991-01-01T23:59:59.000Z

260

Radio imaging of the Subaru/XMM–Newton Deep Field – I. The 100-?Jy catalogue, optical identifications, and the nature of the faint radio source population  

Science Journals Connector (OSTI)

......the stellar bulge (e.g. Ferrarese Merritt 2000; Gebhardt et al. 2000). Radio...Fellowship, respectively. The authors thank Nick Seymour for providing the data used to...MNRAS, 167, 31 p. Ferrarese L. , Merritt D., 2000, ApJ, 539, L9. Fioc M......

Chris Simpson; Alejo Martínez-Sansigre; Steve Rawlings; Rob Ivison; Masayuki Akiyama; Kazuhiro Sekiguchi; Tadafumi Takata; Yoshihiro Ueda; Mike Watson

2006-10-21T23:59:59.000Z

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.


261

Probing the extended emission-line region in 3C 171 with high-frequency radio polarimetry  

Science Journals Connector (OSTI)

......assuming it is cospatial with the EELR, would be 1010 Mo. 1 See http://info.aoc.nrao.edu/vla/html/highfreq/hffastswitch.html 2 See http://info.aoc.nrao.edu/vla/html/refpt.shtml Acknowledgments: The National Radio......

M.J. Hardcastle

2003-02-21T23:59:59.000Z

262

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

263

Production of Seamless Superconducting Radio Frequency Cavities from Ultra-fine Grained Niobium, Phase II Final Report  

SciTech Connect (OSTI)

The positron and electron linacs of the International Linear Collider (ILC) will require over 14,000, nine-cell, one meter length, superconducting radio frequency (SRF) cavities [ILC Reference Design Report, 2007]. Manufacturing on this scale will benefit from more efficient fabrication methods. The current methods of fabricating SRF cavities involve deep drawing of the halves of each of the elliptical cells and joining them by high-vacuum, electron beam welding, with at least 19 circumferential welds per cavity. The welding is costly and has undesirable effects on the cavity surfaces, including grain-scale surface roughening at the weld seams. Hydroforming of seamless tubes avoids welding, but hydroforming of coarse-grained seamless tubes results in strain-induced surface roughening. Surface roughness limits accelerating fields, because asperities prematurely exceed the critical magnetic field and become normal conducting. This project explored the technical and economic feasibility of an improved processing method for seamless tubes for hydroforming. Severe deformation of bulk material was first used to produce a fine structure, followed by extrusion and flow-forming methods of tube making. Extrusion of the randomly oriented, fine-grained bulk material proceeded under largely steady-state conditions, and resulted in a uniform structure, which was found to be finer and more crystallographically random than standard (high purity) RRR niobium sheet metal. A 165 mm diameter billet of RRR grade niobium was processed into five, 150 mm I.D. tubes, each over 1.8 m in length, to meet the dimensions used by the DESY ILC hydroforming machine. Mechanical properties met specifications. Costs of prototype tube production were approximately twice the price of RRR niobium sheet, and are expected to be comparable with economies of scale. Hydroforming and superconducting testing will be pursued in subsequent collaborations with DESY and Fermilab. SRF Cavities are used to construct particle accelerators for high-energy physics research, as well as for lower energy particle accelerators, and Free Electron Lasers. These machines have applications in the fields of basic science, industrial processing, medical diagnostics, pharmaceutical research and weapons systems. The scientific community and the general public will benefit from the implementation of this technology since lower production costs will increase the availability of SRF particle accelerators.

Roy Crooks, Ph.D., P.E.

2009-10-31T23:59:59.000Z

264

A frequency domain model for 3 kV dc traction dc-side resonance identification  

SciTech Connect (OSTI)

Frequency-dependent effects in railway traction power systems arise from the impedance of substation and locomotive line filters and the traction line. Harmonic noise from traction drives and substations can excite resonances and produce overcurrent or overvoltage conditions at critical points in the network. In this paper, the harmonic feeding impedances of a 3 kV DC traction system seen from the rectifier substation, locomotive drive converter and pantograph terminals are presented. Several substation and locomotive filters are considered with a frequency-dependent traction line. Resonances attributed to the substation filter, locomotive filter and traction line are separate and distinct, the line introducing poles and zeros in the audio frequency (AF) range which vary in frequency and magnitude with locomotive position.

Hill, R.J. [Univ. of Bath (United Kingdom). School of Electronic and Electrical Engineering] [Univ. of Bath (United Kingdom). School of Electronic and Electrical Engineering; Fracchia, M.; Pozzobon, P.; Sciutto, G. [Univ. degli Studi di Genova (Italy). Dipt. di Ingegneria Elettrica] [Univ. degli Studi di Genova (Italy). Dipt. di Ingegneria Elettrica

1995-08-01T23:59:59.000Z

265

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

266

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

267

The effect of oxygen flow rate and radio frequency plasma power on cubic ZnMgO ultraviolet sensors grown by plasma-enhanced molecular beam epitaxy  

SciTech Connect (OSTI)

Cubic Zn{sub 1-x}Mg{sub x}O thin films were produced by Plasma-Enhanced Molecular Beam Epitaxy. Oxygen flow rate and applied Radio-Frequency (RF) plasma power were varied to investigate the impact on film growth and optoelectronic device performance. Solar-blind and visible-blind detectors were fabricated with metal-semiconductor-metal interdigitated Ni/Mg/Au contacts and responsivity is compared under different growth conditions. Increasing oxygen flow rate and RF plasma power increased Zn incorporation in the film, which leads to phase segregation at relatively high Zn/Mg ratio. Responsivity as high as 61 A/W was measured in phase-segregated ZnMgO visible-blind detectors.

Casey Boutwell, R.; Wei Ming; Schoenfeld, Winston V. [CREOL, College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816-2700 (United States)

2013-07-15T23:59:59.000Z

268

Criteria of radio-frequency ring-shaped hollow cathode discharge using H{sub 2} and Ar gases for plasma processing  

SciTech Connect (OSTI)

In order to achieve high-density capacitively coupled plasma, a radio-frequency (RF) ring-shaped hollow cathode discharge has been developed as a candidate for processing plasma sources. The plasma density in the hollow cathode discharge reaches a high magnitude of 10{sup 10}-10{sup 11} cm{sup -3}. The RF ring-shaped hollow cathode discharge depends on the pressure and mass of the working gas. Criteria required for producing a RF ring-shaped hollow cathode discharge have been investigated for various gas pressures using H{sub 2} and Ar gases for high-density plasma production. The results reveal that the criteria for the occurrence of the hollow cathode effect are that the trench width should be approximately equal to the sum of the electron-neutral mean free paths and twice the sheath thickness of the RF powered electrode.

Ohtsu, Yasunori; Kawasaki, Yujiro [Department of Electrical and Electronic Engineering, Graduate School of Science and Engineering, Saga University, 1 Honjo-machi, Saga 840-8502 (Japan)

2013-01-21T23:59:59.000Z

269

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

270

Shallow acceptor and hydrogen impurity in p-type arsenic-doped ZnMgO films grown by radio frequency magnetron sputtering  

Science Journals Connector (OSTI)

Arsenic-doped ZnMgO films were fabricated on SiO2 by the radio frequency magnetron sputtering technique at different substrate temperatures during growth. The yielded films were characterized by room temperature Hall measurement, x-ray diffraction, x-ray photoelectron spectroscopy, scanning electron microscopy, secondary ion mass spectroscopy, nuclear reaction analysis and low-temperature photoluminescence. As-doped samples grown at low substrate temperature (350 °C) were n-type conducting (n ~ 1018 cm?3), with evidence showing that the hydrogen impurity was an important shallow donor associated with the observed n-type conduction. Conversion of n-type to p-type conduction being observed at the substrate temperature of ~400 °C was associated with the formation of the AsZn(VZn)2 shallow acceptor complex and the drastic reduction of the hydrogen content.

J C Fan; G W Ding; S Fung; Z Xie; Y C Zhong; K S Wong; G Brauer; W Anwand; D Grambole; C C Ling

2010-01-01T23:59:59.000Z

271

Comparative study of atmospheric pressure low and radio frequency microjet plasmas produced in a single electrode configuration  

SciTech Connect (OSTI)

Microsize jet-type plasmas were generated in a single pin electrode structure source for two separate input frequencies of 50 kHz and 13.56 MHz in the ambient air. The copper pin electrode radius was 360 {mu}m, and it was placed in a Pyrex tube with a radius of 3 mm for helium gas supply. Due to the input frequency difference, the generated plasmas showed distinct discharge characteristics for their plasma physical appearances, electrical properties, gas temperatures, and optical properties. Strengths and weaknesses of both plasmas were discussed for further applications.

Kim, Dan Bee; Rhee, J. K.; Gweon, B.; Moon, S. Y.; Choe, W. [Department of Physics, Korea Advanced Institute of Science and Technology, 335 Gwahangno, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

2007-10-08T23:59:59.000Z

272

Comparative study of atmospheric pressure low and radio frequency microjet plasmas produced in a single electrode configuration  

Science Journals Connector (OSTI)

Microsize jet-type plasmas were generated in a single pin electrode structure source for two separate input frequencies of 50 kHz and 13.56 MHz in the ambient air. The copper pin electrode radius was 360 ? m and it was placed in a Pyrex tube with a radius of 3 mm for helium gas supply. Due to the input frequency difference the generated plasmas showed distinct dischargecharacteristics for their plasma physical appearances electrical properties gas temperatures and optical properties. Strengths and weaknesses of both plasmas were discussed for further applications.

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

2007-01-01T23:59:59.000Z

273

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

274

Self-consistent particle modeling of radio frequency discharge in Ar/O{sub 2} mixtures: Effects of crossed electric and magnetic fields and partial pressure  

SciTech Connect (OSTI)

A particle-in-cell/Monte Carlo model is developed to study and analyze the electrical characteristics of the nonequilibrium plasma created by radio frequency (RF) discharge in Ar/O{sub 2} mixtures in the presence of crossed electric and magnetic fields. The method of collision treatment is based on an optimized estimation of the free time flight. The needed basic data--more specifically, the ion-neutral cross sections--are determined first. The simulation conditions are 50 mTorr for the total gas pressure and 200 V for the peak of the RF voltage at a frequency of 13.56 MHz. The magnetic field is varied from 0 to 50 G. The effect of the partial pressure ratio of O{sub 2} in the mixture and the effect of the magnitude of the magnetic field are discussed. In particular, the results show an increase of the plasma density that is ten times higher in the presence of a magnetic field.

Benyoucef, Djilali [University of Toulouse, UMR CNRS 5213, Laplace, Toulouse (France); Laboratoire Genie Electrique et Energie Renouvelables, Chlef University (Algeria); Yousfi, Mohammed [University of Toulouse, UMR CNRS 5213, Laplace, Toulouse (France); Belmadani, Bachir [Laboratoire Genie Electrique et Energie Renouvelables, Chlef University (Algeria)

2011-04-15T23:59:59.000Z

275

High-power radio frequency pulse generation and extration based on wakefield excited by an intense charged particle beam in dielectric-loaded waveguides.  

SciTech Connect (OSTI)

Power extraction using a dielectric-loaded (DL) waveguide is a way to generate high-power radio frequency (RF) waves for future particle accelerators, especially for two-beam-acceleration. In a two-beam-acceleration scheme, a low-energy, high-current particle beam is passed through a deceleration section of waveguide (decelerator), where the power from the beam is partially transferred to trailing electromagnetic waves (wakefields); then with a properly designed RF output coupler, the power generated in the decelerator is extracted to an output waveguide, where finally the power can be transmitted and used to accelerate another usually high-energy low-current beam. The decelerator, together with the RF output coupler, is called a power extractor. At Argonne Wakefield Accelerator (AWA), we designed a 7.8GHz power extractor with a circular DL waveguide and tested it with single electron bunches and bunch trains. The output RF frequency (7.8GHz) is the sixth harmonic of the operational frequency (1.3GHz) of the electron gun and the linac at AWA. In single bunch excitation, a 1.7ns RF pulse with 30MW of power was generated by a single 66nC electron bunch passing through the decelerator. In subsequent experiments, by employing different splitting-recombining optics for the photoinjector laser, electron bunch trains were generated and thus longer RF pulses could be successfully generated and extracted. In 16-bunch experiments, 10ns and 22ns RF pulses have been generated and extracted; and in 4-bunch experiments, the maximum power generated was 44MW with 40MW extracted. A 26GHz DL power extractor has also been designed to test this technique in the millimeter-wave range. A power level of 148MW is expected to be generated by a bunch train with a bunch spacing of 769ps and bunch charges of 20nC each. The arrangement for the experiment is illustrated in a diagram. Higher-order-mode (HOM) power extraction has also been explored in a dual-frequency design. By using a bunch train with a bunch spacing of 769ps and bunch charges of 50nC each, 90.4MW and 8.68MW of extracted power levels are expected to be reached at 20.8GHz and 35.1GHz, respectively. In order to improve efficiency in HOM power extraction, a novel technique has been proposed to suppress unintended modes.

Gao, F.; High Energy Physics; Illinois Inst. of Tech

2009-07-24T23:59:59.000Z

276

Characteristics of high-purity Cu thin films deposited on polyimide by radio-frequency Ar/H2 atmospheric-pressure plasma jet  

Science Journals Connector (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 H2 to Ar plasma on film characteristics. Theoretical fitting of the OH emission line in OES spectrum revealed that adding H2 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 H2 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.

P. Zhao; W. Zheng; Y. D. Meng; M. Nagatsu

2013-01-01T23:59:59.000Z

277

Effects of the shielding cylinder and substrate on the characteristics of an argon radio-frequency atmospheric glow discharge plasma jet  

SciTech Connect (OSTI)

With unique features of low breakdown voltages, large and uniform discharge areas and high concentrations of chemically reactive species, radio-frequency, atmospheric-pressure glow discharge (rf APGD) plasma sources produced with bare-metallic electrodes have shown promising prospects in the field of materials processing. In this paper, the spatial distributions (i.e., the directly measured integrated axial distribution and the radial distribution by using the inverse Abel transform) of the emission intensities of the Ar I 696.5 nm line are studied for the argon rf APGD plasma jet under different operation conditions, including variations of the rf power input or the argon flow rate, the existence of the solid shielding cylinder or the substrate. The experimental results show that, with other parameters being unchanged, the emission intensities of the Ar I 696.5 nm line increase with increasing the rf power input or the argon flow rate; and the solid shielding cylinder has more significant influences on the characteristics of the plasma impinging jet by reducing the mass flow rate of the ambient air entrained into the plasma jet region than those for the cases without the existence of the substrate at the downstream of the plasma torch nozzle exit.

Li Guo; Le Peisi; Li Heping; Bao Chengyu [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China)

2010-05-15T23:59:59.000Z

278

Radio frequency emission from high-pressure xenon arcs: A systematic experimental analysis of the underlying near-anode plasma instability  

SciTech Connect (OSTI)

High-pressure Xe discharge lamps at DC operation can show unwanted strong RF (radio-frequency) emission to beyond 1 GHz, correlated to a sharp periodic lamp-voltage instability in the near-anode plasma with a pulse repetition rate {epsilon} of 1-10 MHz. The physical origin of the instability is unclear. Here, its existence and pulse rate have been measured as a function of arc current I = 0.2-1.2 A and anode temperature T{sub a} = 1700-3400 K independently, in experimental lamps with pure-tungsten electrodes and a Xe operating pressure around p = 10 MPa. Surprisingly, the instability is not affected by I or current density j but exists if T{sub a} is lower than a threshold value around 2800-2900 K. The pulse rate {epsilon} is simply a rising linear function of the inverse anode temperature 1/T{sub a}, with only a small I-dependent correction. The average anode heat load is slightly lower in the unstable regime and possibly depends on {epsilon}. The results allow a consistent re-interpretation of earlier and present experimental observations and should be both a valuable help in practical lamp engineering and a tight constraint for future theories of this effect.

Hechtfischer, Ulrich [Philips Lighting, GBU Automotive Lamps, Technology, Philipsstrasse 8, 52068 Aachen (Germany)

2011-10-01T23:59:59.000Z

279

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

280

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, Hüseyin

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281

Self consistent radio-frequency wave propagation and peripheral direct current plasma biasing: Simplified three dimensional non-linear treatment in the 'wide sheath' asymptotic regime  

SciTech Connect (OSTI)

A minimal two-field fluid approach is followed to describe the radio-frequency (RF) wave propagation in the bounded scrape-off layer plasma of magnetic fusion devices self-consistently with direct current (DC) biasing of this plasma. The RF and DC parts are coupled by non-linear RF and DC sheath boundary conditions at both ends of open magnetic field lines. The physical model is studied within a simplified framework featuring slow wave (SW) only and lateral walls normal to the straight confinement magnetic field. The possibility is however kept to excite the system by any realistic 2D RF field map imposed at the outer boundary of the simulation domain. The self-consistent RF + DC system is solved explicitly in the asymptotic limit when the width of the sheaths gets very large, for several configurations of the RF excitation and of the target plasma. In the case of 3D parallelepipedic geometry, semi-analytical results are proposed in terms of asymptotic waveguide eigenmodes that can easily be implemented numerically. The validity of the asymptotic treatment is discussed and is illustrated by numerical tests against a quantitative criterion expressed from the simulation parameters. Iterative improvement of the solution from the asymptotic result is also outlined. Throughout the resolution, key physical properties of the solution are presented. The radial penetration of the RF sheath voltages along lateral walls at both ends of the open magnetic field lines can be far deeper than the skin depth characteristic of the SW evanescence. This is interpreted in terms of sheath-plasma wave excitation. Therefore, the proper choice of the inner boundary location is discussed as well as the appropriate boundary conditions to apply there. The asymptotic scaling of various quantities with the amplitude of the input RF excitation is established.

Colas, L.; Jacquot, J.; Hillairet, J.; Goniche, M. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Heuraux, S.; Faudot, E. [IJL-P2M UMR 7198 CNRS, F-54506 Vandoeuvre les Nancy (France); Crombe, K. [Department of Applied Physics, Ghent University, B-9000 Ghent (Belgium); Kyrytsya, V. [LPP-ERM/KMS, Association Euratom-'Belgian State', TEC Partner, Brussels (Belgium)

2012-09-15T23:59:59.000Z

282

Radio Astronomy: Conflict of Frequencies  

Science Journals Connector (OSTI)

...300 per year, and the cost to the government for...per-sons imiade invalid bs par.asitic diseases...price, consult your local Nuclear-Chicago sales engineer...us. NUC:0-6-247 NUCLEAR-CHICAGO CORPORATION...Photometric Titralyzer costs $3300. Write today for...

G. W. Swenson Jr.; R. N. Bracewell

1967-02-03T23:59:59.000Z

283

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

284

Large scale simulations of solar type III radio bursts: flux density, drift rate, duration and bandwidth  

E-Print Network [OSTI]

Non-thermal electrons accelerated in the solar corona can produce intense coherent radio emission, known as solar type III radio bursts. This intense radio emission is often observed from hundreds of MHz in the corona down to the tens of kHz range in interplanetary space. It involves a chain of physical processes from the generation of Langmuir waves to nonlinear processes of wave-wave interaction. We develop a self-consistent model to calculate radio emission from a non-thermal electron population over large frequency range, including the effects of electron transport, Langmuir wave-electron interaction, the evolution of Langmuir waves due to non-linear wave-wave interactions, Langmuir wave conversion into electromagnetic emission, and finally escape of the electromagnetic waves. For the first time we simulate escaping radio emission over a broad frequency range from 500~MHz down to a few MHz and infer key properties of the radio emission observed: the onset (starting) frequency, {identification as fundament...

Ratcliffe, H; Reid, H A S

2014-01-01T23:59:59.000Z

285

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

286

High-frequency self-aligned graphene transistors with transferred gate stacks  

Science Journals Connector (OSTI)

...2009 ) Radio-frequency electrical...Epitaxial-graphene RF field-effect...2011 ) High-frequency, scaled graphene...of high-frequency measurement...Information (PDF) High-frequency self-aligned...attention for radio-frequency transistor...

Rui Cheng; Jingwei Bai; Lei Liao; Hailong Zhou; Yu Chen; Lixin Liu; Yung-Chen Lin; Shan Jiang; Yu Huang; Xiangfeng Duan

2012-01-01T23:59:59.000Z

287

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

288

ASTWG-Owned Sampling Equipment Available for NMFS-Wide Surveys Dual-Frequency Identification Sonar (DIDSON)  

E-Print Network [OSTI]

Underwater Vehicle (AUV) The Fetch 3.5 AUV was designed to be a relatively low-cost system that can be hand quality images for detection and identification of targets underwater (http. The system is setup to be deployed autonomously but has a ~20 ft. cable for testing. Fetch Autonomous

289

A newsletter for non-scientists (and scientists) interested in MAGIC Radars transmit pulses of radio waves of a given frequency and receive signals that are  

E-Print Network [OSTI]

and the speed of propagation of radio waves, which is the speed of light. To understand why the Doppler effect by the distance to the object and the speed of light. As all oscillations travel the same distance and at the same of the Doppler effect in everyday life is the radar gun, whether used for measuring the speed of baseballs

290

The Rapidly Pulsating Radio Source in Vulpecula  

Science Journals Connector (OSTI)

...ob-served frequencies (Table 1...the pulse radio frequency as a function...is the % plasma frequency...near 100 Mhz are given...fre-quency (RF) as a function of frequency. The straight...those at 430 Mhz by 0.279...than the plasma and cyclotron...arrival time at high frequency. High Low...

F. D. Drake; E. J. Gundermann; D. L. Jauncey; J. M. Comella; G. A. Zeissig; H. D. Craft Jr.

1968-05-03T23:59:59.000Z

291

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-Deschênes, M -A; Moneti, A; Monte, C; Montier, L; Morgante, G; Mortlock, D; Munshi, D; Murphy, A; Naselsky, P; Natoli, P; Nestoras, I; Netterfield, C B; Nieppola, E; Nilsson, K; 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

292

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

293

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

294

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

295

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

296

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

297

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"

298

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

299

Use of Dual Frequency Identification Sonar to Determine Adult Chinook Salmon (Oncorhynchus tshawytscha) Escapement in the Secesh River, Idaho ; Annual Report, January 2008 – December 2008.  

SciTech Connect (OSTI)

Chinook salmon in the Snake River basin were listed as threatened under the Endangered Species Act in 1992 (NMFS 1992). The Secesh River represents the only stream in the Snake River basin where natural origin (wild) salmon escapement monitoring occurs at the population level, absent a supplementation program. As such the Secesh River has been identified as a long term salmon escapement and productivity monitoring site by the Nez Perce Tribe Department of Fisheries Resources Management. Salmon managers will use this data for effective population management and evaluation of the effect of conservation actions on a natural origin salmon population. The Secesh River also acts as a reference stream for supplementation program comparison. Dual frequency identification sonar (DIDSON) was used to determine adult spring and summer Chinook salmon escapement in the Secesh River in 2008. DIDSON technology was selected because it provided a non-invasive method for escapement monitoring that avoided listed species trapping and handling incidental mortality, and fish impedance related concerns. The DIDSON monitoring site was operated continuously from June 13 to September 14. The first salmon passage was observed on July 3. DIDSON site total estimated salmon escapement, natural and hatchery fish, was 888 fish {+-} 65 fish (95% confidence interval). Coefficient of variation associated with the escapement estimate was 3.7%. The DIDSON unit was operational 98.1% of the salmon migration period. Adult salmon migration timing in the Secesh River occurred over 74 days from July 3 to September 14, with 5,262 total fish passages observed. The spawning migration had 10%, median, and 90% passage dates of July 8, July 16, and August 12, respectively. The maximum number of net upstream migrating salmon was above the DIDSON monitoring site on August 27. Validation monitoring of DIDSON target counts with underwater optical cameras occurred for species identification. A total of 860 optical camera identified salmon passage observations were identical to DIDSON target counts. However, optical cameras identified eight jack salmon (3 upstream, 5 downstream) less than 55 cm in length that DIDSON did not count as salmon because of the length criteria employed ({ge} 55 cm). Precision of the DIDSON technology was evaluated by comparing estimated net upstream salmon escapement and associated 95% confidence intervals between two DIDSON sonar units operated over a five day period. The DIDSON 1 salmon escapement was 145.7 fish ({+-} 2.3), and the DIDSON 2 escapement estimate was 150.5 fish ({+-} 5). The overlap in the 95% confidence intervals suggested that the two escapement estimates were not significantly different from each other. Known length salmon carcass trials were conducted in 2008 to examine the accuracy of manually measured lengths, obtained using DIDSON software, on high frequency files at a 5 m window length. Linear regression demonstrated a highly significant relationship between known lengths and manually measured salmon carcass lengths (p < 0.0001). A positive bias in manual length measurement of 6.8% to 8% existed among the two observers in the analysis. Total Secesh River salmon escapement (natural origin and hatchery) in 2008 was 912 fish. Natural origin salmon escapement in the entire Secesh River drainage was 847 fish. The estimated natural origin spawner abundance was 836 fish. Salmon spawner abundance in 2008 increased by three fold compared to 2007 abundance levels. The 10 year geometric mean natural origin spawner abundance was 538 salmon and was below the recommended viable population threshold level established by the ICTRT (2007). One additional Snake River basin salmon population was assessed for comparison of natural origin salmon spawner abundance. The Johnson Creek/EFSF Salmon River population had a 10 year geometric mean natural origin spawner abundance of 254 salmon. Salmon spawner abundance levels in both streams were below viable population thresholds. DIDSON technology has been used in the Secesh River to determine salmo

Kucera, Paul A. [Nez Perce Tribe Department of Fisheries Resources Management

2009-06-26T23:59:59.000Z

300

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

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

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

302

radioCherenkov.dvi  

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

. . Coherent radio Cherenkov radiation detectors: Revised February 2013 by S.R. Klein (LBNL/UC Berkeley) 100 10 10 -4 10 -3 10 -5 1.0 0.1 0.01 E 2 I(E ν ) [GeV m -2 s -1 sr -1 ] E ν [GeV] ν NuMoon 10 9 10 10 10 11 10 12 10 13 10 14 10 15 ATCA (no SSR) ATCA (SSR incl.) RICE ANITA Central GZK ν flux predictions Central GZK ν flux predictions Figure 1: Representative ν flux limits from radio-detection experiments, illustrating the energy ranges for different techniques. Shown are limits from the Rice, ANITA, NuMoon and Lunaska (ATCA) collaborations. NuMoon and Lunaska are low and high frequency lunar scans respectively, showing the strengths of the two different frequency bands. The two limits for ATCA are for different models of the lunar regolith; their separation is a measure of the resultant uncertainty. Also shown, for comparison is the mid-range of flux predictions

303

Buoyant radio plasma in clusters of galaxies  

Science Journals Connector (OSTI)

......observing frequency of 330 MHz. In these maps the major...observing frequency is 330 MHz and for the redshift...volume-filling factor of the radio plasma is unity. The units...to note that the hot plasma remains confined within...explosions in the Earth's atmosphere. In their wake the bubbles......

M. Brüggen; C.R. Kaiser

2001-08-01T23:59:59.000Z

304

Radio Frequency Signals in Jupiter's Atmosphere  

Science Journals Connector (OSTI)

...IMAGE OF A LARGE UPWARD ELECTRICAL-DISCHARGE...RINNERT K , HDB ATMOSPHERIC ELEC 27 ( 1995...MEASUREMENTS OF THE RF CHARACTERISTICS...JUPITER PLASMA-WAVE OBSERVATIONS...OBSERVATIONS OF UPPER ATMOSPHERIC OPTICAL FLASHES...Solar and thermal radiation...relatively large at the beginning...and about non-radiative...sensitive area of 6...

L. J. Lanzerotti; K. Rinnert; G. Dehmel; F. O. Gliem; E. P. Krider; M. A. Uman; J. Bach

1996-05-10T23:59:59.000Z

305

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

306

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

307

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

308

Recycling for radio astronomy  

Science Journals Connector (OSTI)

......research-article Features Recycling for radio astronomy Melvin Hoare Professor of Astrophysics at the...space missions, carry out single-dish radio astronomy and boost existing radio-astronomy interferometer arrays, objectives that bring......

Melvin Hoare

2012-02-01T23:59:59.000Z

309

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

310

E-Print Network 3.0 - alcator c-mod radio Sample Search Results  

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

on Alcator C-Mod Summary: tokamak experiments on Alcator C-Mod. LHCD along with Ion Cyclotron Radio Frequency (ICRF) heating... Commissioning of the Lower Hybrid Current...

311

Observing, modeling and predicting the effects of solar radio bursts on radio communications  

Science Journals Connector (OSTI)

The Sun is a source of broadband radio noise which can reach significantly high levels during outbursts associated with the time evolution of the activity cycle. The statistics point out that the maximum occurrence frequency and intensity of solar radio bursts (SRBs) are observed in the proximity of the activity maximum but relevant phenomena can occur also in the raising and declining phases of the cycle. Both theoretical estimations based on extensive statistical analyses carried out in recent years and direct observations performed in the past solar activity cycle indicate that solar radio bursts can interfere wireless communications as well as Global Navigation Satellite Systems (GNSS). In this work we briefly review the theoretical basis and the experimental evidences to date and we show the effectiveness of fast multichannel solar radiopolarimeters like the Trieste Solar Radio System in monitoring and predicting solar radio noise increase in the framework of Space Weather applications.

Mauro Messerotti

2008-01-01T23:59:59.000Z

312

Discrimination between Jovian radio emissions and Saturn electrostatic discharges  

E-Print Network [OSTI]

vertical streaks in the dynamic spectrum of the Cassini/RPWS (Radio and Plasma Wave Science) receiver in the frequency range of a few MHz can be due to Jovian radio emissions or SEDs (Saturn electrostatic discharges caused by lightning in Saturn's atmosphere. We show a method for discriminating between these two

Gurnett, Donald A.

313

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.

314

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

315

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

316

Radio Research During 1959  

Science Journals Connector (OSTI)

... range of work carried out at the Radio Research Station, Slough, and at the substation in Singapore*.

W. J. G. BEYNON

1961-02-18T23:59:59.000Z

317

Success for radio astronomy  

Science Journals Connector (OSTI)

......August 2000 news News Success for radio astronomy Jim Cohen of Jodrell Bank Observatory...mm-wave spectrum. As a result, radio astronomy is now officially allocated most of the...International Mobile Telecommunications). Radio astronomy made its gains in the mm-wave region......

Jim Cohen

2000-08-01T23:59:59.000Z

318

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

319

Prediction of Channel State for Cognitive Radio Using Higher-Order Hidden Markov Model  

E-Print Network [OSTI]

-- Spectrum sensing detects the availability of the radio frequency spectrum, which is essential and vital to cognitive radio. Traditional techniques for spectrum sensing fail to take the latency between spectrum spectrum. It introduces "intelligence" beyond software defined radio (SDR). Spectrum sensing (SS

Qiu, Robert Caiming

320

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

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

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.

322

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.

323

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

324

Underground radio technology saves miners and emergency response personnel  

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

Underground radio technology saves miners and emergency response Underground radio technology saves miners and emergency response personnel Underground radio technology saves miners and emergency response personnel Founded through LANL, Vital Alert Technologies, Inc. (Vital Alert) has launched a wireless, two-way real-time voice communication system that is effective through 1,000+ feet of solid rock. April 3, 2012 Vital Alert's C1000 mine and tunnel radios use magnetic induction, advanced digital communications techniques and ultra-low frequency transmission to wirelessly provide reliable 2-way voice, text, or data links through rock strata and other solid media. Vital Alert's C1000 mine and tunnel radios use magnetic induction, advanced digital communications techniques and ultra-low frequency transmission to wirelessly provide reliable 2-way voice, text, or data links through rock

325

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

326

Discovery of a Radio Flare from GRB 990123  

E-Print Network [OSTI]

We report the discovery of a radio counterpart to GRB 990123. In contrast to previous well-studied radio afterglows which rise to peak flux on a timescale of a week and then decay over several weeks to months, the radio emission from this GRB was clearly detected one day after the burst, after which it rapidly faded away. The simplest interpretation of this ``radio flare'' is that it arises from the reverse shock. In the framework of the afterglow models discussed to date, a forward shock origin for the flare is ruled out by our data. However, at late times, some radio afterglow emission (commensurate with the observed late-time optical emission, the optical afterglow) is expected from the forward shock. The relative faintness of the observed late-time radio emission provides an independent indication for a jet-like geometry in this GRB. We use the same radio observations to constrain two key parameters of the forward shock, peak flux and peak frequency, to within a factor of two. These values are inconsistent with the notion advocated by several authors that the prompt optical emission detected by ROTSE smoothly joins the optical afterglow emission. Finally, with hindsight we now recognize another such radio flare and this suggests that one out of eight GRBs has a detectable radio flare. This abundance coupled with the reverse shock interpretation suggests that the radio flare phenomenon has the potential to shed new light into the physics of reverse shocks in GRBs.

S. R. Kulkarni; D. A. Frail; R. Sari; G. H. Moriarty-Schieven; D. S. Shepherd; P. Udomprasert; A. C. S. Readhead; J. S. Bloom; M. Feroci; E. Costa

1999-03-30T23:59:59.000Z

327

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

328

EIA Radio test  

U.S. Energy Information Administration (EIA) Indexed Site

September 10, 2012 September 10, 2012 Test of Energy News Radio Service This is a test audio file of the U.S. Energy Information Administration's energy news radio service to be launched on Tuesday, September 11 th with the release of EIA's monthly Short-Term Energy Outlook. EIA's radio service will provide free short broadcast stories on EIA energy data reports and analysis to radio stations nationwide. The stories will be recorded in MP3 format and can be downloaded from EIA's radio service webpage at www.eia.gov/radio. The first broadcast stories will be posted around noon Eastern Time on Sept. 11 after the release of EIA's monthly Short Term Energy Outlook forecast. These initial stories will focus on the outlook for U.S. gasoline prices, crude oil production and natural gas production.

329

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

330

Telecommunications Radio Lease  

E-Print Network [OSTI]

Telecommunications Radio Lease 1. Fax completed form to 979.847.1111. 2. If you do not receive to any of the radios, chargers and accessories until signed back over to the Telecommunications office Telecommunications Office Use Only Service Due Date Installation Cost (NRC) Billed To Telephone/Circuit Number

331

Telecommunications Radio Rental  

E-Print Network [OSTI]

Telecommunications Radio Rental 1. Fax completed form to 979.847.1111. 2. If you do not receive of the radios, chargers and accessories until signed back over to the Telecommunications office. Amount Work Order Prepared Departmental Approval Signature Date Service Date Desired Telecommunications Office

332

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

333

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

334

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

335

E-Print Network 3.0 - accurate frequency dependent Sample Search...  

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

-induced errors. TRINAV synergistically combines the use of GPS with a ground-based radio-frequency (RF) ... Source: Pennycook, Steve - Materials Science and Technology...

336

The spectral structure and energetics of powerful radio sources  

E-Print Network [OSTI]

Determining the energy spectrum of an electron population can give key insights into the underlying physics of a radio source; however, the lack of high resolution, broad-bandwidth observations has left many ambiguities in our understanding of radio galaxies. The improved capabilities of telescopes such as the JVLA and LOFAR mean that within the bandwidth of any given observation, a detailed spectral shape can now be produced. We present recent investigations of powerful FR-II radio galaxies at GHz and MHz frequencies and show for the first time their small-scale spectral structure. We highlight problems in traditional methods of analysis and demonstrate how these issues can now be addressed. We present the latest results from low frequency studies which suggest a potential increase in the total energy content of radio galaxy lobes with possible implications for the energetics of the population as a whole.

Harwood, J J; Croston, J H; Stroe, A; Morganti, R; Orru, E

2014-01-01T23:59:59.000Z

337

"Did you pack your keys?" Smart Objects And Forgetfulness  

E-Print Network [OSTI]

of ten light-emitting diodes (LEDs), piezo and Radio Frequency Identification Reader (RFID) connected

Purver, Matthew

338

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

339

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

340

Low Cost Radio Telescope  

Science Journals Connector (OSTI)

A radio interferometer has been constructed at Haverford College as an aid to learning the fundamentals of radio astronomy. Its cost both in cash outlay and in construction time make it a feasible year-long project for an undergraduate. Its simplicity does not prevent it from being a useful instrument for instruction at the college or high-school level; among its capabilities are the measurement of the positions of at least four of the strongest discrete cosmic-noisesources and the diameter of the radio sun.

Joseph H. Taylor Jr.

1964-01-01T23:59:59.000Z

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

Temporal mechanisms underlying flicker detection and identification for red–green and achromatic stimuli  

Science Journals Connector (OSTI)

We have simultaneously measured detection and temporal frequency identification for both red–green isoluminant and achromatic stimuli over a range of temporal frequencies for two...

Metha, Andrew B; Mullen, Kathy T

1996-01-01T23:59:59.000Z

342

CRAF Handbook for Radio Astronomy  

E-Print Network [OSTI]

CRAF Handbook for Radio Astronomy EUROPEAN SCIENCE FOUNDATION Committee on Radio Astronomy. It represents all scientific disciplines: physical and engineering sciences, life, earth and environmental Handbook for Radio Astronomy, 3rd edition". #12;CRAF Handbook for Radio Astronomy Edited by Jim Cohen

Rodriguez, Luis F.

343

Nomenclature of The Galactic Center Radio Sources  

E-Print Network [OSTI]

Since its identification as the Galactic Center, the radio source Sagittarius A has been a target of intense research. Due to the high density of sources in the Galactic Center and differing observing techniques, the nomenclature of sources in this region has changed over the years, with sources having several names, as well as the same names being used for different sources. We review this historical evolution in the context of current and previous scientific discussions, and outline how, why and when some of the commonly accepted names of Galactic Center sources were established.

Patrick Palmer; W. Miller Goss

1996-07-29T23:59:59.000Z

344

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.

345

ELECTRON-BEAM-INDUCED RADIO EMISSION FROM ULTRACOOL DWARFS  

SciTech Connect (OSTI)

We present the numerical simulations for an electron-beam-driven and loss-cone-driven electron-cyclotron maser (ECM) with different plasma parameters and different magnetic field strengths for a relatively small region and short timescale in an attempt to interpret the recent discovered intense radio emission from ultracool dwarfs. We find that a large amount of electromagnetic (EM) field energy can be effectively released from the beam-driven ECM, which rapidly heats the surrounding plasma. A rapidly developed high-energy tail of electrons in velocity space (resulting from the heating process of the ECM) may produce the radio continuum depending on the initial strength of the external magnetic field and the electron beam current. Both significant linear polarization and circular polarization of EM waves can be obtained from the simulations. The spectral energy distributions of the simulated radio waves show that harmonics may appear from 10 to 70{nu}{sub pe} ({nu}{sub pe} is the electron plasma frequency) in the non-relativistic case and from 10 to 600{nu}{sub pe} in the relativistic case, which makes it difficult to find the fundamental cyclotron frequency in the observed radio frequencies. A wide frequency band should therefore be covered by future radio observations.

Yu, S.; Doyle, J. G.; Kuznetsov, A. [Armagh Observatory, College Hill, Armagh BT61 9DG (United Kingdom); Hallinan, G. [California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 (United States); Antonova, A. [Department of Astronomy, St. Kliment Ohridski University of Sofia, 5 James Bourchier Blvd., 1164 Sofia (Bulgaria); MacKinnon, A. L. [School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Golden, A., E-mail: syu@arm.ac.uk [Price Center, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY 10461 (United States)

2012-06-10T23:59:59.000Z

346

Bursty synchrotron intensity variations of Jovian 6-cm radio emissions and Jupiter's quasi-periodic polar activities  

Science Journals Connector (OSTI)

......low-frequency (nu 0.7 MHz) beamed radio bursts...low-frequency (nu 0.7 MHz) beamed radio bursts...observations (10-20 kHz) of Ulysses during...polar field lines and plasmas (Halekas et al...bandwidth of 100-490 MHz and an antenna efficiency...measurements for atmospheric effects and the antenna......

Yu-Qing Lou; Huagang Song; Yinyu Liu; Meng Yang

2012-03-01T23:59:59.000Z

347

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...

348

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

349

E-Print Network 3.0 - astrosphere collapse frequency Sample Search...  

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

First, mon- itor the low-frequency heliospheric radio emissions. Second, survey plasma waves... of daily averaged higher frequency fluctuations up to 0.25 Hz over 16 min...

350

Radio Receiver Design  

Science Journals Connector (OSTI)

... local oscillator and then through the intermediate-frequency amplifier to the second detector giving an audio-frequency output. The present volume ends at this stage, leaving ... -frequency output. The present volume ends at this stage, leaving audio-frequency amplifiers and power supplies to be dealt with in Part 2. ...

1943-06-12T23:59:59.000Z

351

Designing solution-processable air-stable liquid crystalline crosslinkable semiconductors  

Science Journals Connector (OSTI)

...liquid crystal (LC) displays, flexible organic light emitting diode displays, low frequency radio frequency identification...liquid crystal (LC) displays, flexible organic light emitting diode displays, low frequency radio frequency identification...

2006-01-01T23:59:59.000Z

352

Spectrally efficient hybrid multiplexing and demultiplexing schemes toward the integration of microwave and millimeter-wave radio-over-fiber systems in a WDM-PON infrastructure  

Science Journals Connector (OSTI)

Hybrid multiplexing and demultiplexing schemes with the capability to integrate microwave and millimeter-wave frequency radio-over-fiber signals in a wavelength division multiplexed...

Bakaul, Masuduzzaman; Nirmalathas, Ampalavanapillai; Lim, Christina; Novak, Dalma; Waterhouse, Rod

2009-01-01T23:59:59.000Z

353

The diffuse radio emission around NGC 5580 and NGC 5588  

E-Print Network [OSTI]

The galaxy pair NGC 5580 and NGC 5588 are part of a loose group of galaxies. They are surrounded by steep-spectrum, extended radio emission which was previously suggested to be a down-scaled example of Mpc-size radio haloes present in galaxies clusters. We present a multi-frequency study of the radio-emission aimed to clarify its nature. The source has been observed with the Giant Meterwave Radio Telescope at 235, 325 and 610 MHz and the images obtained were combined with archival data to cover the frequency range 150-1400 MHz. The new observations revealed the presence of a second, fainter lobe on the South-East of NGC 5580. The spectral index study of the source shows a flattening of the spectrum (which implies a younger particle population) close to the two galaxies. We argue that the extended radio emission is the remnant of a past activity cycle of the active galactic nucleus present in NGC 5580 and therefore a notable example of a dying radio galaxy located outside a dense environments.

de Gasperin, F; Williams, W; Brüggen, M; Murgia, M; Beck, R; Bonafede, A

2014-01-01T23:59:59.000Z

354

Ion cyclotron range of frequencies heating of plasma with small impurity production  

DOE Patents [OSTI]

Plasma including plasma ions is magnetically confined by a magnetic field. The plasma has a defined outer surface and is intersected by resonance surfaces of respective common ion cyclotron frequency of a predetermined species of plasma ions moving in the magnetic field. A radio frequency source provides radio frequency power at a radio frequency corresponding to the ion cyclotron frequency of the predetermined species of plasma ions moving in the field at a respective said resonance surface. RF launchers coupled to the radio frequency source radiate radio frequency energy at the resonance frequency onto the respective resonance surface within the plasma from a plurality of locations located outside the plasma at such respective distances from the intersections of the respective resonance surface and the defined outer surface and at such relative phases that the resulting interference pattern provides substantially null net radio frequency energy over regions near and including substantial portions of the intersections relative to the radio frequency energy provided thereby at other portions of the respective resonance surface within the plasma.

Ohkawa, Tihiro (La Jolla, CA)

1987-01-01T23:59:59.000Z

355

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

356

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

357

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

358

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

359

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.

360

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

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

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

362

Special Presentation: Key Findings from the Barrier Immune Radio  

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

Special Presentation: Key Findings from the Barrier Immune Radio Special Presentation: Key Findings from the Barrier Immune Radio Communications Project Speaker(s): Francis Rubinstein Girish Ghatikar Peter Haugen Date: November 29, 2007 - 12:00pm Location: 90-3122 The Barrier Immune Radio Communications (BIRC) Project was established in January 2007 by the Demand Response Emerging Technologies Program (DRETD) to identify radio frequency technologies that could enable the widespread deployment of Demand Response strategies in buildings. Researchers from Lawrence Berkeley National Laboratory and Lawrence Livermore National Laboratory will present the key findings from this project in a one-hour presentation. Researchers found that several of the RF technologies tested at LBNL's Molecular Foundry building were able to provide sufficiently

363

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.

364

Electronics, Radio and Telecommunications  

Science Journals Connector (OSTI)

... a grant-in-aid from the United States National Science Foundation. One of these is Telecommunications (No. 1, 1957. Pp. 1-94. First English issue. Issued in ... the official publication of the A. S. Popov Technical Society of Radio Engineering and Telecommunications. ...

1958-10-11T23:59:59.000Z

365

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

366

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.

367

PEAK FLUX DISTRIBUTIONS OF SOLAR RADIO TYPE-I BURSTS FROM HIGHLY RESOLVED SPECTRAL OBSERVATIONS  

SciTech Connect (OSTI)

Solar radio type-I bursts were observed on 2011 January 26 by high resolution observations with the radio telescope AMATERAS in order to derive their peak flux distributions. We have developed a two-dimensional auto burst detection algorithm that can distinguish each type-I burst element from complex noise storm spectra that include numerous instances of radio frequency interference (RFI). This algorithm removes RFI from the observed radio spectra by applying a moving median filter along the frequency axis. Burst and continuum components are distinguished by a two-dimensional maximum and minimum search of the radio dynamic spectra. The analysis result shows that each type-I burst element has one peak flux without double counts or missed counts. The peak flux distribution of type-I bursts derived using this algorithm follows a power law with a spectral index between 4 and 5.

Iwai, K. [Nobeyama Solar Radio Observatory, National Astronomical Observatory of Japan, Nobeyama, Nagano 384-1305 (Japan); Masuda, S.; Miyoshi, Y. [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya, Aichi 464-8601 (Japan); Tsuchiya, F.; Morioka, A.; Misawa, H., E-mail: kazumasa.iwai@nao.ac.jp [Planetary Plasma and Atmospheric Research Center, Tohoku University, Sendai, Miyagi 980-8578 (Japan)

2013-05-01T23:59:59.000Z

368

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

369

Grating formation by a high power radio wave in near-equator ionosphere  

SciTech Connect (OSTI)

The formation of a volume grating in the near-equator regions of ionosphere due to a high power radio wave is investigated. The radio wave, launched from a ground based transmitter, forms a standing wave pattern below the critical layer, heating the electrons in a space periodic manner. The thermal conduction along the magnetic lines of force inhibits the rise in electron temperature, limiting the efficacy of heating to within a latitude of few degrees around the equator. The space periodic electron partial pressure leads to ambipolar diffusion creating a space periodic density ripple with wave vector along the vertical. Such a volume grating is effective to cause strong reflection of radio waves at a frequency one order of magnitude higher than the maximum plasma frequency in the ionosphere. Linearly mode converted plasma wave could scatter even higher frequency radio waves.

Singh, Rohtash; Sharma, A. K.; Tripathi, V. K. [Department of Physics, Indian Institute of Technology Delhi, New Delhi-110016 (India)

2011-11-15T23:59:59.000Z

370

On the Possibility of Curvature Radiation from Radio Pulsars  

E-Print Network [OSTI]

We consider the widespread hypothesis that coherent curvature radiation is responsible for the radio emission of pulsars. The comparison of energy conservation and the published data and luminosities explicitely proves that coherent curvature radiation cannot be the source for the radio emission of pulsars for frequencies below a few GHz. At higher frequencies coherent curvature radiation can be ruled out because neither the observationally deduced emission heights nor the observed radius to frequency mapping can be reproduced by this mechanism. Our argumentation is in accordance with the more general critics (e.g. Melrose 1992) that no adequate bunching mechanism has been identified for coherent curvature radiation. We present 5 examples (0329+29, 0355+54, 0540+23, 1133+16, 1916+10) of pulsars whose high frequency (larger than 1.4. GHz, up to 32 GHz) luminosities are well known, and as a low frequency example the faintest radio pulsar 0655+64 of the Taylor et al (1993) sample.

H. Lesch; A. Jessner; M. Kramer; Th. Kunzl

1998-01-26T23:59:59.000Z

371

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

372

Solar radioastronomy with the LOFAR (LOw Frequency ARray) radio telescope  

E-Print Network [OSTI]

-240 MHz. It will have a large collecting area achieved using active dipole techniques, and will have place in the Sun's atmosphere. Study of these emissions with LOFAR will make possible major advances to inhomogeneities in the ionosphere's electron plasma content, and hence refractive index) that plague low

373

Solar radioastronomy with the LOFAR (LOw Frequency ARray) radio telescope  

E-Print Network [OSTI]

range 10­240 MHz. It will have a large collecting area achieved using active dipole techniques taking place in the Sun's atmosphere. Study of these emissions with LOFAR will make possible major to inhomogeneities in the ionosphere's electron plasma content, and hence refractive index) that plague low

White, Stephen

374

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

375

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

376

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.

377

Radio-frequency stabilization of a nonequilibrium plasma accelerator  

Science Journals Connector (OSTI)

Results of experimental studies of the effect of an external RF field on the excitation of oscillations in a magnetoplasmadynamic plasma accelerator are presented. It is found that applying an RF field can suppre...

K. P. Kirdyashev

2011-08-01T23:59:59.000Z

378

A plasma cathode for a radio-frequency gun  

Science Journals Connector (OSTI)

A plasma ferroelectric cathode is used to form electron ... high charge in an electron bunch in an rf electron gun of a 10-cm wavelength ... . The operation of the cathode in the rf gun was studied experimentally...

V. A. Kushnir; I. V. Khodak

2008-09-01T23:59:59.000Z

379

Radio frequency discharge with control of plasma potential distribution  

SciTech Connect (OSTI)

A RF discharge plasma generator with additional electrodes for independent control of plasma potential distribution is proposed. With positive biasing of this ring electrode relative end flanges and longitudinal magnetic field a confinement of fast electrons in the discharge will be improved for reliable triggering of pulsed RF discharge at low gas density and rate of ion generation will be enhanced. In the proposed discharge combination, the electron energy is enhanced by RF field and the fast electron confinement is improved by enhanced positive plasma potential which improves the efficiency of plasma generation significantly. This combination creates a synergetic effect with a significantly improving the plasma generation performance at low gas density. The discharge parameters can be optimized for enhance plasma generation with acceptable electrode sputtering.

Dudnikov, Vadim [Muons, Inc., Batavia, Illinois 60510 (United States); Dudnikov, A. [BINP, Novosibirsk 63090 (Russian Federation)

2012-02-15T23:59:59.000Z

380

Negative ions in a radio-frequency oxygen plasma  

Science Journals Connector (OSTI)

A systematic study of a low pressure (5–200 mTorr) oxygen discharge is presented. Measurements of the electron and negative ion densities in the 13.56 MHz capacitively coupled plasma are performed by means of a microwave resonance technique in combination with photodetachment. A kinetic model is developed, incorporating volume and wall reactions of ions as well as neutral species. It is shown, by matching the experimental results with the model, that the dominant ion is O- whereas the O2- and O3- densities reach 10 to 20 % of the total negative ion density. The ratio of negative ion to electron density varies between 5 and 10 and decreases with pressure and rf power. The total negative ion density is about 5×1015 m-3, it increases with gas flow, is independent of the rf input power, and has a maximum at a pressure of 30 mTorr. The agreement between the measurements and the model is within the experimental error for a wide range of conditions. Deviations are explained by changes in the gas and wall temperatures. From the known ion density the effective ionization rate has been determined and related to the electron temperature. The ionization temperature obtained in this way varies between 2 and 4 eV and decreases with increasing gas pressure and power, as expected for the bulk electron temperature in this type of discharge.

E. Stoffels; W. W. Stoffels; D. Vender; M. Kando; G. M. W. Kroesen; F. J. de Hoog

1995-03-01T23:59:59.000Z

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.


381

Charged-species profiles in electronegative radio-frequency plasmas  

Science Journals Connector (OSTI)

The negative ion density profile in a low pressure oxygen rf plasma has been measured by a photodetachment technique. At an rf power of 10 W and a neutral pressure of 10 mTorr, a parabolic negative ion density profile is obtained with a peak density of 8×1015 m-3 and a maximum ratio of negative ion to electron densities n-/ne?18. Under these conditions, the most abundant positive ion, determined by ion mass spectrometry, is O2+ with O+ being less than 10% of the positive ion density. The most abundant negative ion is O- with O2- and O3- being less than 20% of the total negative charge density. The maximum in the density profile of negative ions shifts closer to the powered rf electrode as the pressure is increased in the asymmetric system. Comparison of the results to theory indicates that the asymmetry follows from an enhancement of the ionization rate near the powered electrode sheath. The parabolic profile is also obtained in CCl2F2 at low pressure. Simulations and measurements show a rapid drop in ion density near the sheath that may be related to the recently discussed ‘‘stratification’’ phenomenon in electronegative plasmas.

D. Vender; W. W. Stoffels; E. Stoffels; G. M. W. Kroesen; F. J. de Hoog

1995-03-01T23:59:59.000Z

382

Surface plasma source with saddle antenna radio frequency plasma generator  

SciTech Connect (OSTI)

A prototype RF H{sup -} surface plasma source (SPS) with saddle (SA) RF antenna is developed which will provide better power efficiency for high pulsed and average current, higher brightness with longer lifetime and higher reliability. Several versions of new plasma generators with small AlN discharge chambers and different antennas and magnetic field configurations were tested in the plasma source test stand. A prototype SA SPS was installed in the Spallation Neutron Source (SNS) ion source test stand with a larger, normal-sized SNS AlN chamber that achieved unanalyzed peak currents of up to 67 mA with an apparent efficiency up to 1.6 mA/kW. Control experiments with H{sup -} beam produced by SNS SPS with internal and external antennas were conducted. A new version of the RF triggering plasma gun has been designed. A saddle antenna SPS with water cooling is fabricated for high duty factor testing.

Dudnikov, V.; Johnson, R. P. [Muons, Inc., Batavia, Illinios 60510 (United States); Murray, S.; Pennisi, T.; Piller, C.; Santana, M.; Stockli, M.; Welton, R. [ORNL, Oak Ridge, Tennessee 37831 (United States)

2012-02-15T23:59:59.000Z

383

Observation of Radio-Frequency Confinement of a Plasma  

Science Journals Connector (OSTI)

The breakdown field in a microwave cavity excited in the electric quadrupole mode exhibits a plateau at pressures below the electron mean-free-path limit of diffusion-controlled breakdown. The luminosity of a steady-state plasma in this domain exhibits a maximum at the central nodal point in the cavity field. These results are interpreted as evidence of rf confinement of a low-density plasma.

Charles F. Shelby and Albert J. Hatch

1972-09-25T23:59:59.000Z

384

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

385

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...

386

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

387

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

388

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...

389

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

390

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

391

Optical Patch Antennas - Analysis and Design inspired by Radio Frequency  

Science Journals Connector (OSTI)

Optical antennas have been quite instrumental in manipulating light in subwavelength scales. Considering their significant resemblance to RF counterparts, computational tools of patch...

Unal, Gul Seda; Aksun, M Irsadi

392

Mapping subsurface fractures by radio-frequency holography: a simulation  

Science Journals Connector (OSTI)

......B. , 1970. Handbook of Electromagnetic...entropy image restoration in astronomy...Aperture and Array System Design, Including...be equal to a power of 2. magnitude...is equal to a power of 2. We assume...B., 1970. Handbook of Electromagnetic...entropy image restoration in astronomy......

Paul Lorrain

1991-08-01T23:59:59.000Z

393

Radio frequency analog electronics based on carbon nanotube transistors  

E-Print Network [OSTI]

, and Hong Zhang** Departments of *Physics, Materials Science and Engineering, §Electrical and Computer Engineering, and ¶Chemistry, Beckman Institute for Advanced Science and Technology, and Frederick Seitz, RF mixers, and audio amplifiers. These results represent important first steps to practical

Rogers, John A.

394

Power Supplies and Radio Frequency Department at Culham  

E-Print Network [OSTI]

power to the JET and MAST nuclear fusion experiments at Culham. Culham is fed from the grid at 400kMW 800tonne flywheel-driven generators, high current and high voltage DC switches in pulsed supplies

395

Audio-Frequency Radio Waves from the Sun  

Science Journals Connector (OSTI)

... in the study, we have constructed a large loop antenna, connected to a tunable audio amplifier. With this device, we have detected the existence of variations of the order ...

DONALD H. MENZEL; WINFIELD W. SALISBUBY

1948-01-17T23:59:59.000Z

396

Uniting Legislation with RFID Privacy-Enhancing Technologies Melanie R. Rieback, Bruno Crispo, Andrew S. Tanenbaum  

E-Print Network [OSTI]

response by modulating the request signal using one or more subcarrier frequencies. These RFID tags can do. Keywords: Radio frequency identification, security, privacy, data protection legislation, privacy- enhancing technologies. 1 Introduction Radio Frequency Identification (RFID) technology faces security

Tanenbaum, Andrew S.

397

Gene Frequency  

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

Gene Frequency Gene Frequency Name: donna Location: N/A Country: N/A Date: N/A Question: If six fingers is a dominant human trait why do we have only five? Replies: This is simple. There are just not many genes in the human population for six fingers. Steve Sample Look in any high school biology book for what is known as Hardy-Weinberg equilibrium. These two scientists (separately) said that gene frequencies do not change much unless something in the environment selects them over other genes. In other words, unless 6 fingers somehow becomes an advantage, and five-fingered people have less of an advantage, the frequency of six fingered people in the population will not necessarily increase. This is the same reason that recessive traits don't disappear from the population. Also, six fingers is not considered attractive and they may not get as many mates. Also, more people are born with six fingers than you might imagine but just have them amputated shortly after birth.

398

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.

399

basic exchange telecommunications radio service  

Science Journals Connector (OSTI)

A service that extends telecommunications service to rural, outlying, and remote...Common abbreviation BETRS. Note: In the basic exchange telecommunications radio service (BETRS), the (a)....

2001-01-01T23:59:59.000Z

400

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.


401

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

402

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

403

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

404

SEMI-SUPERVISED NOVELTY DETECTION WITH ADAPTIVE EIGENBASES, AND APPLICATION TO RADIO TRANSIENTS  

E-Print Network [OSTI]

drawn attention to a new class of sources. Fast transients are rare pulses of radio-frequency energy multiple antenna power measurements that could include hundreds of time steps and frequency channels interesting candidates for storage and later exhaustive analysis. · Nonstationarity: Background noise

Wagstaff, Kiri L.

405

A Simple Method of Producing Wide-Band Frequency Modulation  

Science Journals Connector (OSTI)

... THE resistance-capacity tuned oscillator is well known as a very good generator of audio-frequency oscillations. In a recent communication by Rakshit and Bhattacharyya1 it was pointed out ... out that the conventional circuit of a three-phase system, with components selected for producing audio-frequency oscillations, invariably generates radio-frequencies by virtue of the unavoidable stray and inter- ...

H. RAKSHIT; N. SARKAR

1949-04-09T23:59:59.000Z

406

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

407

The future for radio astronomy  

Science Journals Connector (OSTI)

......research-article Features The future for radio astronomy Rene P Breton Tom Hassall Rene P Breton and Tom Hassall, School of Physics and Astronomy, University of Southampton, UK; r...Tom Hassall argue that, while radio astronomy has always involved transient phenomena......

Rene P Breton; Tom Hassall

2013-12-01T23:59:59.000Z

408

Cooperation in Cognitive Radio Networks  

Science Journals Connector (OSTI)

The operation of cognitive radio (CR) networks involves opportunistic access to the spectrum licensed to primary users (PUs) by secondary users (SUs). Traditionally, this access is performed in such a way that the PUs suffer minimal interference to their ... Keywords: cognitive radio networks, cooperation, cooperative relays

Pedro Smith Coutinho, José Ferreira de Rezende, Valmir Carneiro Barbosa

2014-05-01T23:59:59.000Z

409

Radio Monitoring Birds of Prey  

Science Journals Connector (OSTI)

Abstract This paper is a consideration of field techniques rather than of equipment design. The first of three parts reviews applications of radio monitoring in bird of prey studies, with suggestions concerning terminology. There has been some radio telemetry of activity and incubation parameters, but most monitoring of raptors has involved radio tracking. This has included location of birds for investigation of movements, ranges, habitat utilization and roost sites, but could also be used for surveillance of what birds were doing. The second section describes techniques used in radio surveillance of a particularly secretive raptor, the goshawk, and presents original data on prey selection which were collected during studies of predation on woodpigeons and pheasants. Finally, there is an outline of how selection data were combined with predation rate measurements and hawk density estimates, obtained using radio tags as a Lincoln Index marker during hawk sightings, to determine the impact of predation on these economically important prey.

R.E. KENWARD

1980-01-01T23:59:59.000Z

410

Nonequilibrium atmospheric pressure plasma jet using a combination of 50?kHz/2?MHz dual-frequency power sources  

Science Journals Connector (OSTI)

An atmospheric pressure plasma jet is generated by dual sinusoidal wave (50?kHz and 2?MHz). The dual-frequency plasma jet exhibits the advantages of both low frequency and radio frequency plasmas namely the long plasma plume and the high electron density. The radio frequency ignition voltage can be reduced significantly by using dual-frequency excitation compared to the conventional radio frequency without the aid of the low frequency excitation source. A larger operating range of ? mode discharge can be obtained using dual-frequency excitation which is important to obtain homogeneous and low-temperature plasma. A larger controllable range of the gas temperature of atmospheric pressure plasma could also be obtained using dual-frequency excitation.

Yong-Jie Zhou; Qiang-Hua Yuan; Fei Li; Xiao-Min Wang; Gui-Qin Yin; Chen-Zhong Dong

2013-01-01T23:59:59.000Z

411

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

412

Measurement of electron temperatures and electron energy distribution functions in dual frequency capacitively coupled CF4/O2 plasmas using  

E-Print Network [OSTI]

emission spectroscopy TRG-OES . The parallel plate etcher was powered by a high frequency 60 MHz "source frequency LF source, while the plasma density and ion flux are determined mainly by the high frequency HF-dimensional model of a 2f-CCP driven by the superposition of two sinusoidal radio-frequency rf voltages. They found

Economou, Demetre J.

413

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

414

Non-thermal radio astronomy  

Science Journals Connector (OSTI)

Abstract This presentation starts with Karl Jansky’s discovery of cosmic radio emission in 1933 and notes the striking similarities to Hess’s discovery of cosmic-rays in 1912. At first it was assumed that this radio emission was thermal but in 1939 Grote Reber discovered that it was stronger at longer wavelengths, requiring a non-thermal emission process. These discoveries had a revolutionary impact on astronomy and radio astronomy was born. The interpretation of this non-thermal radiation as synchrotron emission from high energy particles in the interstellar medium did not occur until the late 1940s but then it provided the link between radio astronomy and cosmic-ray research. Ginzburg, in particular, saw that cosmic-ray astrophysics was now possible using radio waves to trace sources of cosmic-rays. We discuss the discovery of extragalactic active galactic nuclei leading to the discovery of quasars and the first evidence for black holes in the nuclei of galaxies. We summarise the present status and future of some of the main radio telescopes used to image the non-thermal emission from external galaxies. Finally, we include a short description of the use of radio signals for the direct detection of cosmic-rays and UHE neutrinos.

R.D. Ekers

2014-01-01T23:59:59.000Z

415

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

416

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

417

PIC–MCC Simulations of Capacitive High-Frequency Discharge Dynamics with Nanoparticles  

Science Journals Connector (OSTI)

A new combined particle-in-cell Monte Carlo collision (PIC–MCC) approach is discussed for accurate and fast simulation of a radio-frequency (rf) discharge at a low gas pressure and high plasma density. Test calcu...

Irina V. Schweigert

2010-01-01T23:59:59.000Z

418

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

419

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

420

Measurements of ion cyclotron range of frequencies mode converted wave intensity with phase contrast imaging in Alcator C-Mod and comparison with full-wave simulations  

E-Print Network [OSTI]

Radio frequency waves in the ion cyclotron range of frequencies (ICRF) are widely used to heat tokamak plasmas. In ICRF heating schemes involving multiple ion species, the launched fast waves convert to ion cyclotron waves ...

Jaeger, E. F.

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

Radio galaxies and local quasars  

Science Journals Connector (OSTI)

... through the gas and magnetic fields near the galaxy which ejected them. This would produce synchroton radio emission in great strength and over a long time, drawing its power from ...

JAMES TERRELL

1975-11-13T23:59:59.000Z

422

Determination of radio-frequency phase in harmonic frequency modulation spectroscopy  

Science Journals Connector (OSTI)

We have devised two useful schemes to determine the rf phase of the modulation waveforms in harmonic FM spectroscopy, a novel technique that we reported recently for the removal of...

Shum, Chi Man; Whittaker, Edward A

1991-01-01T23:59:59.000Z

423

CO2 laser frequency stabilization using the radio-frequency optogalvanic Lamb dip  

Science Journals Connector (OSTI)

The Lamb dip of the CO2 saturation signal in an extracavity low-pressure CO2–N2 rf glow discharge is detected optogalvanically and used to stabilize...

Tsai, Chin-Chun; Lin, Tyson; Shieh, Cherng-Yn; Yen, Tsu-Chiang; Shy, Jow-Tsong

1991-01-01T23:59:59.000Z

424

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

425

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

426

Study of a dual frequency atmospheric pressure corona plasma  

Science Journals Connector (OSTI)

Radio frequency mixing of 2 and 13.56 MHz was investigated by performing experimental measurements on the atmospheric pressurecoronaplasma. As a result of the dual frequency length current density and electron excitation temperature of the plasma were increased while the gas temperature was maintained at roughly the same level when compared to the respective single frequency plasmas. Moreover observation of time-resolvedimages revealed that the dual frequency plasma has a discharge mode of 2 MHz positive streamer 2 MHz negative glow and 13.56 MHz continuous glow.

Dan Bee Kim; S. Y. Moon; H. Jung; B. Gweon; Wonho Choe

2010-01-01T23:59:59.000Z

427

Study of a dual frequency atmospheric pressure corona plasma  

SciTech Connect (OSTI)

Radio frequency mixing of 2 and 13.56 MHz was investigated by performing experimental measurements on the atmospheric pressure corona plasma. As a result of the dual frequency, length, current density, and electron excitation temperature of the plasma were increased, while the gas temperature was maintained at roughly the same level when compared to the respective single frequency plasmas. Moreover, observation of time-resolved images revealed that the dual frequency plasma has a discharge mode of 2 MHz positive streamer, 2 MHz negative glow, and 13.56 MHz continuous glow.

Kim, Dan Bee; Moon, S. Y.; Jung, H.; Gweon, B.; Choe, Wonho [Department of Physics, Korea Advanced Institute of Science and Technology, 335 Gwahangno, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

2010-05-15T23:59:59.000Z

428

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...

Szadkowski, Zbigniew; Timmermans, C

2014-01-01T23:59:59.000Z

429

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

430

Radio detection of high-energy cosmic rays at the Pierre Auger Observatory  

E-Print Network [OSTI]

The southern Auger Observatory provides an excellent test bed to study the radio detection of extensive air showers as an alternative, cost-effective, and accurate tool for cosmic-ray physics. The data from the radio setup can be correlated with those from the well-calibrated baseline detectors of the Pierre Auger Observatory. Furthermore, human-induced radio noise levels at the southern Auger site are relatively low. We have started an R&D program to test various radio-detection concepts. Our studies will reveal Radio Frequency Interferences (RFI) caused by natural effects such as day-night variations, thunderstorms, and by human-made disturbances. These RFI studies are conducted to optimise detection parameters such as antenna design, frequency interval, antenna spacing and signal processing. The data from our initial setups, which presently consist of typically 3 - 4 antennas, will be used to characterise the shower from radio signals and to optimise the initial concepts. Furthermore, the operation of a large detection array requires autonomous detector stations. The current design is aiming at stations with antennas for two polarisations, solar power, wireless communication, and local trigger logic. The results of this initial phase will provide an important stepping stone for the design of a few tens kilometers square engineering array

A. M. van den Berg; for the Pierre Auger Collaboration

2007-08-13T23:59:59.000Z

431

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

432

First Results of the 74 MHz VLA-Pie Town Link. Hercules A at Low Frequencies  

E-Print Network [OSTI]

We present the results of the first successful observations of the Pie Town link with the Very Large Array (VLA) at 74 MHz on Hercules A. The improvement in resolution from 25 arcsec to 10 arcsec resolves the helical- and ring-like features seen at higher frequencies. We also present new high dynamic range images of this powerful radio galaxy at 325 MHz. Our low frequency observations confirm the multiple outburst interpretation of the spectral index differences at high frequencies. Comparison between our radio and ROSAT X-ray data does not reveal any association between the X-ray emission from the cluster and the radio lobes. There are no extra regions of radio emission at 74 MHz.

Nectaria A. B. Gizani; A. Cohen; N. E. Kassim

2005-01-21T23:59:59.000Z

433

A Coordinated Radio Afterglow Program  

E-Print Network [OSTI]

We describe a ground-based effort to find and study afterglows at centimeter and millimeter wavelengths. We have observed all well-localized gamma-ray bursts in the Northern and Southern sky since BeppoSAX first started providing rapid positions in early 1997. Of the 23 GRBs for which X-ray afterglows have been detected, 10 have optical afterglows and 9 have radio afterglows. A growing number of GRBs have both X-ray and radio afterglows but lack a corresponding optical afterglow.

D. A. Frail; S. R. Kulkarni; M. H. Wieringa; G. B. Taylor; G. H. Moriarty-Schieven; D. S. Shepherd; R. M. Wark; R. Subrahmanyan; D. McConnell; S. J. Cunningham

1999-12-08T23:59:59.000Z

434

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

435

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

436

The Radio Afterglow From GRB 980519: A Test of the Jet and Circumstellar Models  

E-Print Network [OSTI]

We present multi-frequency radio observations from the afterglow of GRB 980519 beginning 7.2 hours after the gamma-ray burst and ending 63 days later. The fast decline in the optical and X-ray light curves for this burst has been interpreted either as afterglow emission originating from a collimated outflow -- a jet -- or the result of a blast wave propagating into a medium whose density is shaped by the wind of an evolved massive star. These two models predict divergent behavior for the radio afterglow, and therefore, radio observations are capable, in principle, of discriminating between the two. We show that a wind model describes the subsequent evolution of the radio afterglow rather well. However, we see strong modulation of the light curve, which we interpret as diffractive scintillation. These variations prevent us from decisively rejecting the jet model.

D. A. Frail; S. R. Kulkarni; R. Sari; G. B. Taylor; D. S. Shepherd; J. S. Bloom; C. H. Young; L. Nicastro; N. Masetti

1999-10-04T23:59:59.000Z

437

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

438

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

439

Radio observations of the M8.1 solar flare of 23 June, 1988: Evidence for energy transport by thermal processes  

Science Journals Connector (OSTI)

The Very Large Array (VLA) and the frequency agile interferometer at the Owens Valley Radio Observatory (OVRO) were used to observe the M8.1 flare of 23 June, 1988. The VLA obtained images prior to and during ...

T. S. Bastian; D. E. Gary

1992-06-01T23:59:59.000Z

440

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, Hüseyin

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

The environments of FRII radio sources  

Science Journals Connector (OSTI)

......radio-emitting plasma, as argued by Kaiser...used total 178-MHz flux densities from...about the external atmosphere. 1 As discussed...radio-emitting plasma altogether from...X-ray-emitting atmospheres. Although many...radio-emitting plasma. It is then a coincidence......

M. J. Hardcastle; D. M. Worrall

2000-12-01T23:59:59.000Z

442

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

443

Paper 629: HF Radio Mesh Networks 1 Abstract--Wireless mesh networks provide robust connec-  

E-Print Network [OSTI]

the solar and terrestrial environments, and the ability to com- municate directly between arbitrary pairs to refract radio frequency energy back to Earth from altitudes of of up to a few hundred km. This beyond line a skip zone, but is limited by terrain or man-made obstacles. 3) Near-Vertical Incidence Skywave (NVIS

Johnson, Eric E.

444

COMPLEX RADIO SPECTRAL ENERGY DISTRIBUTIONS IN LUMINOUS AND ULTRALUMINOUS INFRARED GALAXIES  

SciTech Connect (OSTI)

We use the Expanded Very Large Array to image radio continuum emission from local luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs) in 1 GHz windows centered at 4.7, 7.2, 29, and 36 GHz. This allows us to probe the integrated radio spectral energy distribution (SED) of the most energetic galaxies in the local universe. The 4-8 GHz flux densities agree well with previous measurements. They yield spectral indices {alpha} {approx} -0.67 (where F {sub {nu}}{proportional_to}{nu}{sup {alpha}}) with {+-}0.15 (1{sigma}) scatter, typical of nonthermal (synchrotron) emission from star-forming galaxies. The contrast of our 4-8 GHz data with literature 1.5 and 8.4 GHz flux densities gives further evidence for curvature of the radio SED of U/LIRGs. The SED appears flatter near {approx}1 GHz than near {approx}6 GHz, suggesting significant optical depth effects at lower frequencies. The high-frequency (28-37 GHz) flux densities are low compared to extrapolations from the 4-8 GHz data. We confirm and extend to higher frequency a previously observed deficit of high-frequency radio emission for luminous starburst galaxies.

Leroy, Adam K.; Evans, Aaron S.; Condon, James [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903-2475 (United States); Momjian, Emmanuel; Ott, Juergen; Meier, David S. [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States); Murphy, Eric [Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Armus, Lee; Haan, Sebastian; Mazzarella, Joseph M.; Surace, Jason [Spitzer Science Center, California Institute of Technology, MC 314-6, Pasadena, CA 91125 (United States); Privon, George C. [Department of Astronomy, University of Virginia, 530 McCormick Road, Charlottesville, VA 22904 (United States); Schinnerer, Eva; Walter, Fabian [Max Planck Institut fuer Astronomie, Koenigstuhl 17, Heidelberg D-69117 (Germany)

2011-09-20T23:59:59.000Z

445

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

446

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.

447

High frequency rectenna  

DOE Patents [OSTI]

The invention provides an inexpensive array of rectifying antennas which employ field emission diodes for rectifying electromagnetic waves of microwave frequencies and higher frequencies.

Logan, B. Grant (Danville, CA); Orvis, William J. (Livermore, CA)

1991-01-01T23:59:59.000Z

448

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

449

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

450

An Optimal Feedback Approach to Particle Source Identification in Tokamaks  

E-Print Network [OSTI]

hybrid radio frequency antenna in the experimental nuclear fusion tokamak reactor Tore Supra. A deeper on input estimation and model validation for transport phenomena described by partial differential influenced by the LH input power PLH [3]. Indeed, a small but significant part of this power is absorbed

Paris-Sud XI, Université de

451

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

452

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

453

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

454

CXAllenRadioTower2.pdf  

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

Southwestern Power Administration proposes to modify and reconstruct its Allen Radio Tower communications site as part of the Spectrum Relocation project. Categorical...

455

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

456

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

457

Agile Testing Methods for IC Radios.  

E-Print Network [OSTI]

??This thesis concentrates on the development of a new testing procedure for the radio used in Broadcom?s WLAN and cellular chips. Verification and hardware testing… (more)

Martinez, Luis

2011-01-01T23:59:59.000Z

458

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

459

A diffuse bubble-like radio-halo source MRC 0116+111: imprint of AGN feedback in a low-mass cluster of galaxies  

Science Journals Connector (OSTI)

......with the cluster atmosphere in the inner core...buoyantly rising plasma bubble is also...16.69 621-MHz radio luminosity...frequency 400 MHz. The low-frequency...100 kpc scale) plasma bubbles shows...Between 240 and 621 MHz (GMRT) both...the hot cluster atmosphere. Such uprising......

Joydeep Bagchi; Joe Jacob; Gopal-Krishna; Norbert Werner; Nitin Wadnerkar; Jaydeep Belapure; A. C. Kumbharkhane

2009-10-21T23:59:59.000Z

460

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

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

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

462

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

463

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

464

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.

465

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

466

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

467

Multi-radio medium access control protocol for wireless sensor networks  

Science Journals Connector (OSTI)

This paper describes a dual-radio based medium access control protocol for wireless sensor networks. Our protocol combines the advantages of the two radios operating in different frequency bands to result in highly energy-efficient operation. The design effectively addresses the two dominant sources of energy consumption in sensor network communication, namely the idle listening and the ephemeral burst data traffic. This paper presents the design rationale and extensive empirical performance evaluation of the protocol in terms of power consumption and latency under various traffic loads and duty cycles. Experimental performance comparison with B-MAC show high gains of our approach. We derive analytical expression for the optimum transmit power level ratio of the two radios giving minimum energy consumption. We also model the mathematical relationship for the optimal duty cycle of the nodes to a given network traffic load and validate it through the prototype implementation on commercially available sensor nodes.

Junaid Ansari; Xi Zhang; Petri Mahonen

2010-01-01T23:59:59.000Z

468

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

469

Telecommunications Emergency Alert System (EAS) Radio  

E-Print Network [OSTI]

Telecommunications Emergency Alert System (EAS) Radio 1. Send completed form to Mail Stop will be charged for a replacement. If the radio malfunctions, please contact Telecommunications. Texas A Departmental Approval Signature Date Service Date Desired Telecommunications Office Use Only Service Due Date

470

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.

471

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

Tuðcu, Tuna

472

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

473

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

474

Brightness distribution of synchrotron radiation in the field of a magnetic dipole and the nature of double radio sources  

SciTech Connect (OSTI)

A model of double radio sources is proposed. In it, the radio radiation is produced by the motion of relativistic particles in a dipole magnetic field whose source is the optical galaxy. Calculations of the apparent brightness distribution of the synchroton radiation of electrons in such a field make it possible to explain some observed features of radio sources: a) the double nature of structure, b) the disposition of the components of the double source on a single straight line with the parent galaxy, c) the dependence of the size of the components on the frequency, d) the preferential direction of the field along the principal axis of the source, e) the similarity of the structures of radio sources in wide ranges of linear and angular sizes. Some other features can also be explained.

Zyskin, Y.L.; Stepanyan, A.A.

1985-05-01T23:59:59.000Z

475

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

476

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

477

STEREO-Wind Radio Positioning of an Unusually Slow Drifting Event  

E-Print Network [OSTI]

On 13 March 2010 an unusually long duration event was observed by radio spectrographs onboard the STEREO-B and Wind spacecraft. The event started at about 13:00 UT and ended at approximately 06:00 UT on 14 March. The event presents itself as slow drifting, quasi-continuous emission in a very narrow frequency interval, with an apparent frequency drift from about 625 kHz to approximately 425 kHz. Using the Leblanc, Dulk, and Bougeret (1998) interplanetary density model we determined that the drift velocities of the radio source are $\\approx$33km s$^{-1}$ and $\\approx$52km s$^{-1}$ for 0.2 and 0.5 times the densities of Leblanc model, respectively with a normalization density of 7.2cm$^{-3}$ at 1AU and assuming harmonic emission. A joint analysis of the radio direction finding data, coronograph white-light observations and modeling revealed that the radio sources appear to be localized in regions of interaction with relatively high density and slow solar wind speed.

Martínez-Oliveros, J C; Bain, H; Liu, Y; Pulupa, M; Saint-Hilaire, P; Higgins, P; Krupar, V; Krucker, Säm; Bale, S D

2014-01-01T23:59:59.000Z

478

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

479

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

480

A comprehensive study of the bias and variance of frequency-response-function measurements: Optimal window selection and overlapping strategies  

Science Journals Connector (OSTI)

This paper investigates the measurement errors involved in measuring frequency response functions from weighted-overlapped segment averaging, a technique that has become a standard in modern spectral analysers due to its computational advantages. A particular ... Keywords: Frequency response function, Non-parametric frequency domain identification, Statistical performance analysis, Weighted-overlapped segment averaging

Jérôme Antoni; Johan Schoukens

2007-10-01T23:59:59.000Z

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481

Frequency Combs for Astronomy  

Science Journals Connector (OSTI)

For the first time a mode filtered frequency comb has been used to calibrate an astronomical spectrometer online. Solar and calibration spectra have been recorded simultaneously.

Wilken, Tobias; Hänsch, Theodor W; Udem, Thomas; Steinmetz, Tilo; Holzwarth, Ronald; Araujo-Hauck, Constanza; Pasquini, Luca; D'Odorico, Sandro; Manescau, Antonio; Murphy, Michael T; Kentischer, Thomas; Schmidt, Wolfgang

482

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

483

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

484

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</