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  • 1
    Electronic Resource
    Electronic Resource
    Performance evaluation of the TFTR gyrotron CTS diagnostic for alpha particles : Proceedings of the 9th topical conference on high temperature plasma diagnostics (1992)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 4644-4646 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A large-angle, 60-GHz collective Thomson scattering (CTS) diagnostic system for localized measurements of DT alpha-particle velocity distribution and fraction is being implemented on TFTR. Calculations of expected CTS spectra, signal-to-noise ratio per receiver channel, and estimated error in determining the temperature and fraction of alpha particles are being carried out. The experimental spectra are simulated by adding noise to the theoretical calculation by a Monte Carlo technique. Error analysis is then performed by using a relative intensity calibrated nonlinear curve fitting code to calculate the desired plasma parameters (Ti, Tα, nα/ni). Simulation results indicate that expected background emission of 20 eV during Supershot in TFTR poses no problem to the experiment. Also short integration times (〈10 ms) can be used to resolve the energetic ion features, thus offering a possibility for the study of temporal evolution of energetic ion velocity distribution during a single plasma shot.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1143646
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  • 2
    Electronic Resource
    Electronic Resource
    Characteristics of gyrotron scattering system for α particle diagnostics in TFTR (abstract) : Proceedings of the 9th topical conference on high temperature plasma diagnostics (1992)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 63 (1992), S. 4647-4647 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: In D-T plasmas, the understanding of the physics of confined α particles is extremely valuable for the future fusion plasma device. Among the various proposed α diagnostics, an X-mode collective Thomson scattering system employing a high-power gyrotron source (P(approximately-equal-to)200 kW, f=60 GHz, pulse length (approximately-equal-to)0.5 s, and modulation frequency=10–25 kHz) is being designed for TFTR. The detailed description of the gyrotron source, transmission lines, optical designs, beam and viewing dump design, and receiver system will be presented in this paper. In particular, the test results of the beam and viewing dump indicate that the stray light can be reduced by 60 dB. The background emission level (∼20 eV) near 60-GHz range during high Q discharge may also be reduced with beam and viewing dump further. The optical system is designed to measure the radial profile of α particles and to orient the incident wavevector (k0) to test the electromagnetic effects of the scattered spectrum. Prior to the study of α physics in D-T plasmas, this scattering system will be used to measure not only a bulk ion temperature but also the scattered spectrum due to fast ions produced by NB and ICRF heating in TFTR. This work was supported by the U.S. Department of Energy Contract No. DE-AC02-76-CHO-3073.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1143647
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  • 3
    Electronic Resource
    Electronic Resource
    Development of high-power millimeter and submillimeter wavelength collective Thomson scattering diagnostics for energetic ion measurements in tokamaks : EIGHT TOPICAL CONFERENCE ON HIGH−TEMPERATURE PLASMA DIAGNOSTICS (1990)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 61 (1990), S. 3544-3547 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: High-power, large-angle ((approximately-greater-than)10°), collective Thomson scattering diagnostics can provide localized density and velocity distribution data of confined alpha particles, ICRH simulated alpha particles, and ions related to ICRH and neutral beam energy deposition. Millimeter-wave gyrotron systems are under development for TFTR and JET. Scattering with a submillimeter gyrotron is being investigated for Alcator C-Mod. Major design issues include plasma accessibility, scattering angle, orientation to magnetic field, spectra of non-Maxwellian velocity distributions, signal-to-noise ratio, refraction, electron cyclotron emission, and beam and viewing dumps.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1141567
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  • 4
    Electronic Resource
    Electronic Resource
    Design of a third-harmonic electron cyclotron emission diagnostic for ballooning mode fluctuations in PBX-M : Eight topical conference on high-temperature plasma diagnostics (1990)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 61 (1990), S. 2995-2997 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A third-harmonic electron cyclotron emission diagnostic using ultrawide bandwidth (≈40 GHz) heterodyne receivers centered on 120 GHz with 14 channels per radial view is described for localized, long wavelength (5(approximately-less-than)λ(approximately-less-than)50 cm), fast time response (≈1 μs) fluctuation studies in the PBX-M tokamak. The optically gray emission signal will have a γñe/ne+(3/β)T˜e/Te dependence on temperature and density fluctuations where γ≤1 and 1≤β≤3 depending on local optical depth. Electron temperature fluctuation sensitivity is estimated to be 0.2%≤T˜e/Te ≤2.9% depending on local optical depth and fluctuation frequency in the 0.1–1 MHz range. Spatial resolution of approximately 3 cm radially and 5 cm vertically are estimated for 2 keV plasmas with low suprathermal electron emission.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1141758
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  • 5
    Electronic Resource
    Electronic Resource
    Precision terahertz relative reflectometry using a blackbody source and heterodyne receiver (1994)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 65 (1994), S. 438-444 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Instrumentation for making localized, precise relative reflection measurements of metals and superconductors in the terahertz frequency range is demonstrated. The results can be used to determine the surface resistivity of these materials which is of particular importance to development of high-temperature superconductors. Emission from a commerically available 1000 °C blackbody source was reflected from the materials under test and a reference reflector. The reflected signals were detected by a Schottky diode heterodyne receiver using a CO2-laser-pumped 214.5 μm CH2F2 laser as the local oscillator. Double-sideband bandwidth and receiver noise temperature were 2 GHz and 30 000 K, respectively. The use of a broadband incoherent diagnostic source minimizes instrumentation sensitivity to coherent interference effects. The heterodyne receiver provides for sensitive detection with good spatial and frequency resolution. Unoptimized spatial resolution of four times the diffraction limit was achieved. The potential for relative reflectivity measurement accuracy of better than 0.1% was demonstrated with 30 min measurement times though systematic errors limited actual measurement accuracy to about 0.3%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1145153
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  • 6
    Electronic Resource
    Electronic Resource
    Characterization of β-Amyloid Precursor Proteins With or Without the Protease-Inhibitor Domain Using Anti-Peptide Antibodies (1990)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 55 (1990), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Alternative splicing of the transcript encoding the β-amyloid precursor protein (BAPP) of Alzheimer's disease produces multiple mRNA species. Translation of these mRNAs predicts protein products of 770, 751, and 695 amino acids. The difference arises from the inclusion in BAPP-770/ 751 of a 56-residue insert region which is homologous to Kunitz-type protease inhibitors. We have prepared and affinity-purified anti-peptide antibodies that react specifically with either BAPP-770/751 (inssert-specific) or BAPP-695 (junction-specific). A detectable level of the mRNA corresponding to the BAPP-770/751 protein was found in all cell lines tested. Immunoprecipitation of 35S-labeled proteins from these cell lines showed them to contain one or two Mr 105,000 bands reactive with the insert-specific serum, i-291. In contrast, only cos-7 cells and the human neuroblastoma cell line, IMR-32, contained mRNA species that encode the BAPP 695 protein, as shown by Northern analysis with a junction spanning oligonucleotide probe. A band of Mr 95,000 was immunoprecipitated specifically from these two cell lines using the junction-specific serum, J-284. Indirect immunofluorescence labeling of cells corroborated these findings. All cells reacted with the insert-specific antibodies, i-291 and i 324. Only cos-7 and IMR-32 cells reacted with the junction specific antibody, J-284. These results demonstrate the use fulness of anti-peptide antibodies for the differential detection of the BAPP-695 and BAPP-770/751 proteins.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1990.tb08821.x
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  • 7
    Electronic Resource
    Electronic Resource
    An External Aortic Root Device for Decreasing Aortic Regurgitation: In Vitro and In Vivo Animal Studies (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of cardiac surgery 9 (1994), S. 0 
    Details
    ISSN: 1540-8191
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Objectives: The purpose of this study was to determine if a device placed externally around the aortic root decreases regurgitant flow in acute aortic regurgitation. Background: Aortic regurgitant flow is dependent on central aortic pressure and the aortic root and leaflet geometry. It may be possible to decrease aortic regurgitant severity by reducing aortic root size or dimension changes. Methods: Aortic regurgitation was created in eight calf heart specimens suspended in a continuous flow system. Retrograde and antegrade aortic flow and distending aortic pressure were measured at baseline and after placement of an external aortic device at the level of the aortic annulus. In two additional specimens, the incompetent aortic valve was visualized fiberoptically before and after placement of the external device. Acute aortic regurgitation was created surgically in four live calves by excising a portion of the aortic leaflets. Antegrade and retrograde flow, left ventricular pressure, and central aortic pressure were measured at baseline, after creation of aortic regurgitation, and after placement of the external device. Results: In the in vitro calf specimens, regurgitant flow decreased from 46.9 cc/sec to 15.1 cc/sec (66.0%± 21.8% decrease) after placement of the external device (p 〈 0.001). The regurgitant orifice area decreased from 0.13 ± 0.04 cm2 to 0.04 ± 0.02 cm2 after device placement (p 〈 0.001). Antegrade flow was reduced to a smaller extent (20.0%± 19.2% decrease) by the device (p 〈 0.05). Placement of the device around the aorta resulted in improved coaptation of the leaflets with a marked reduction in defect size by endoscopic visualization. Use of the external aortic device was associated with improvement in aortic regurgitant severity in three of four calves with surgically created aortic regurgitation. Concluslons: In these preliminary studies, acute experimental aortic regurgitant severity is decreased by the use of an external aortic device, probably due to reduction in aortic annular dimension changes and improved aortic leaflet apposition. Further studies are needed to determine the effectiveness of this device in chronic aortic regurgitation. (J Card Surg 1994;9:304–313)
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1540-8191.1994.tb00849.x
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  • 8
    Electronic Resource
    Electronic Resource
    Editor's Note (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of cardiac surgery 8 (1993), S. 0 
    Details
    ISSN: 1540-8191
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1540-8191.1993.tb00406.x
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  • 9
    Electronic Resource
    Electronic Resource
    Editor's Note (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of cardiac surgery 8 (1993), S. 0 
    Details
    ISSN: 1540-8191
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1540-8191.1993.tb00374.x
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  • 10
    Electronic Resource
    Electronic Resource
    Editor's Note (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of cardiac surgery 8 (1993), S. 0 
    Details
    ISSN: 1540-8191
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1540-8191.1993.tb00358.x
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