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  • 1
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Biochimica et Biophysica Acta (BBA)/Molecular Basis of Disease 1097 (1991), S. 205-211 
    ISSN: 0925-4439
    Keywords: (Mouse) ; Developmental variation ; Heavy metal ; Metallothionein mRNA
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine , Physics
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Data from an E(parallel)B charge exchange neutral analyzer (CENA), which views down the axis of a neutral beamline through an aperture in the target chamber calorimeter of the TFTR neutral beam test facility, exhibit two curious effects. First, there is a turn-on transient lasting tens of milliseconds having a magnitude up to three times that of the steady state level. Second, there is a 720 Hz, up to 20% peak-to-peak fluctuation persisting the entire pulse duration. The turn-on transient occurs as the neutralizer/ion source system reaches a new pressure equilibrium following the effective ion source gas throughput reduction by particle removal as ion beam. Widths of the transient are a function of the gas throughput into the ion source, decreasing as the gas supply rate is reduced. Heating of the neutralizer gas by the beam is assumed responsible, with gas temperature increasing as gas supply rate is decreased. At low gas supply rates, the transient is primarily due to dynamic changes in the neutralizer line density and/or beam species composition. Light emission from the drift duct corroborate the CENA data. At high gas supply rates, dynamic changes in component divergence and/or spatial profiles of the source plasma are necessary to explain the observations. The 720 Hz fluctuation is attributed to a 3% peak-to-peak ripple of 720 Hz on the arc power supply amplified by the quadratic relationship between beam divergence and beam current. Tight collimation by CENA apertures cause it to accept a very small part of the ion source's velocity space, producing a signal linearly proportional to beam divergence. Estimated fluctuations in the peak power density delivered to the plasma under these conditions are a modest 3%–8% peak to peak. The effects of both phenomena on the injected neutral beam can be ameliorated by careful operation of the ion sources.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Energy flow within TFTR neutral beamlines is measured with a waterflow calorimetry system capable of simultaneously measuring the energy deposited within four heating beamlines (three ion sources each), or of measuring the energy deposited in a separate neutral beam test stand. Of the energy extracted from the ion source on the well-instrumented test stand, 99.5±3.5% can be accounted for. When the ion deflection magnet is energized, however, 6.5% of the extracted energy is lost. This loss is attributed to a spray of devious particles onto unmonitored surfaces. A 30% discrepancy is also observed between energy measurements on the internal beamline calorimeter and energy measurements on a calorimeter located in the test stand target chamber. Particle reflection from the flat plate calorimeter in the target chamber, which the incident beam strikes at a near-grazing angle of 12°, is the primary loss of this energy. A slight improvement in energy accountability is observed as the beam pulse length is increased. This improvement is attributed to systematic error in the sensitivity of the energy measurement to small fluctuations in the supply water temperature. An overall accuracy of 15% is estimated for the total power injected into TFTR. Contributions to this error are uncertainties in the beam neutralization efficiency, reionization and beam scrape-off in the drift duct, and fluctuations in the temperature of the supply water.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    The @journal of organic chemistry 55 (1990), S. 4011-4019 
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Cambridge : Cambridge University Press
    The @classical quarterly 42 (1992), S. 421-436 
    ISSN: 0009-8388
    Source: Cambridge Journals Digital Archives
    Topics: Classical Studies
    Notes: When Cicero uncovered and suppressed the Catilinarian Conspiracy as consul in 63 B.c., supporters hailed him ‘father of his country’ (pater patriae) and proposed that he be awarded the oak crown normally given to a soldier who had saved the life of a comrade in battle (corona civica). Our sources connect these honours with earlier heroes such as Romulus, Camillus and Marius, but the Elder Pliny writes as if Cicero was the first before Caesar and the Emperors to be given the title pater patriae. Pliny's point may revolve around Senatorial initiative, and assuming this to be the case he really should have stressed that Cicero received the informal support of a limited number of Senators only, whereas Caesar and the Emperors were honoured by formal vote of the entire Senate. Perhaps Pliny was fooled by the prominence of those who spoke on Cicero's behalf, such as Cato, Catulus and Gellius Publicola. Opponents, on the other hand, angrily rejected calls that Cicero be recognised as the saviour of the state. In their eyes his execution of the Catilinarians marked him as a cruel tyrant. Metellus Nepos proposed Pompey's recall from the East in order to free Rome from Cicero's tyranny. Aside from echoes of patria potestas, it seems obvious that the Romans were thinking in terms of the conventional Greek antithesis between the good king who is like a father to his people and the selfish tyrant who treats his subjects as slaves. The Younger Pliny employs the same basic ideas in his Panegyricus: the cruel tyrant Domitian suppressed freedom (libertas) and desired honour as a god (deus, numen); the gentle Trajan is a citizen and father not a tyrant and master (dominus). Tacitus has this basic distinction in mind too. Nevertheless, as is well known, Pliny regularly addresses Trajan not as ‘father’ but as ‘master’ (domine) in Book 10 of his Letters. This was plainly an acceptable practice on the social plane, if not quite yet on the political. Augustus, Tiberius and Claudius indicated their opposition to dominus as a title for themselves, evidently for its connotations of autocracy and servitude. Domitian, damned as a tyrant, was accused of demanding to be addressed as dominus et deus. The title dominus existed from at least the first century A.d. as a common form of polite address between inferiors and superiors of free birth, not only between masters and slaves. It gradually gained acceptance as an official title of the Emperor through the second century and was advertised widely by the Severi. And yet its tone throughout this period could also be critical when understood in terms of the good king/tyrant antithesis.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 130-138 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Analysis of Doppler-shifted Balmer-α line emission from the Tokamak Fusion Test Reactor's (TFTR) neutral beam injection systems has revealed that the line shape, which is a direct measure of the velocity distribution function, is well approximated by the sum of two Gaussians, or, alternatively, by a Lorentzian. For the sum of two Gaussians, the wide-divergence part of the distribution contains 40% of the beam power and has a divergence five times that of the narrow part. Assuming a narrow 1/e-divergence of 1.3° (based on fits to the beam shape on the calorimeter), the wide part has a divergence of 6.9°. The entire line shape is also well approximated by a Lorentzian with a half-maximum divergence of 0.9°. Up to now, most fusion neutral beam modelers have assumed a single Gaussian velocity distribution, at the extraction plane, in each direction perpendicular to beam propagation. This predicts a beam transmission efficiency from the ion source to the calorimeter of 97%. Waterflow calorimetry data, however, yield a transmission efficiency of ∼75%, a value in rough agreement with predictions of the two Gaussian or Lorentzian models presented here. The broad wing of the two Gaussian distribution also accurately predicts the loss in the neutralizer. An additional factor in determining the power density at the surface of beam absorbers is the angle at which the particles arrive. Angles are different for particles emitted from different locations on the ion source. To treat this situation, the average angle of incidence is calculated. For beam loss at the exit of the neutralizer, the average angle of incidence is 2.2°, rather than the 4.95° subtended by the center of the ion source. This average angle of incidence is found to be a function of beam divergence. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 2729-2736 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Tokamak Fusion Test Reactor (TFTR) deuterium neutral beams have been operated unintentionally with significant quantities of extracted water ions. Water has been observed with an optical multichannel analyzer. These leaks were thermally induced with the contamination level increasing linearly with pulse length. Up to 6% of the beam current was attributed to water ions, corresponding to an instantaneous value of 12% at the end of a 1.5 s pulse. A similar contamination is observed during initial operation of ion sources exposed to air. Operation of new ion sources typically produces a contamination level of ∼2%, with cleanup to undetectable levels in 50–100 beam pulses. Approximately 90% of the water extracted from ion sources with water leaks was deuterated, implying that there is the potential for tritiated water production during TFTR's forthcoming DT operation. It is concluded that isotope exchange in the plasma generator takes place rapidly, most likely as the result of surface catalysis. The primary concern is with O implanted into beam absorbers recombining with tritium, and the subsequent retention of T2O on cryopanels.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Determination of two critical neutral beam parameters, power and divergence, are affected by the reflection of a fraction of the incident energy from the surface of the measuring calorimeter. On the TFTR Neutral Beam Test Stand, greater than 30% of the incident power directed at the target chamber calorimeter was unaccounted for. Most of this loss is believed due to reflection from the surface of the flat calorimeter, which was struck at a near grazing incidence (12°). Beamline calorimeters, of a "V''-shape design, while retaining the beam power, also suffer from reflection effects. Reflection, in this latter case, artificially peaks the power toward the apex of the "V,'' complicating the fitting technique, and increasing the power density on axis by 10%–20%; an effect of import to future beamline designers. Agreement is found between measured and expected divergence values, even with 24% of the incident energy reflected.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: 195 tritium ion source shots were injected into Tokamak Fusion Test Reactor (TFTR) high power plasmas during December 1993–March 1994. In addition, four highly diagnosed pulses were fired into the calorimeter. Analysis of the Doppler shifted Tα emission of the beam in the neutralizer has revealed that the extracted ion compositions for deuterium and tritium are indistinguishable: 0.72±0.04 D+; 0.22±0.02 D+2; 0.07±0.01 D+3 compared to 0.72±0.04 T+; 0.23±0.02 T+2; 0.05±0.01 T+3. The resultant tritium full-energy neutral fraction is higher than for deuterium due to the increased neutralization efficiency at lower velocity. To conserve tritium, it was used only for injection and a few calorimeter test shots, never for ion source conditioning. When used, the gas species were switched to tritium only for the shot in question. This resulted in an approximately 2% deuterium contamination of the tritium beam and vice versa for the first deuterium pulse following tritium. Data from the calorimeter shots indicate that tritium contamination of the deuterium beam cleans up in five to six beam pulses, and is reduced to immeasurable quantities prior to deuterium beam injection. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 62 (1991), S. 376-380 
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: During the final deuterium-tritium phases of the TFTR and JET tokamaks half of the neutral injectors will be used to produce tritium neutral beams to maintain an equal mix of deuterium and tritium in the core plasma, and such requirements may also occur in future devices. This will require that the voltage hold off capabilities of the high voltage insulators in the accelerators be unimpaired by any charge buildups associated with the beta decay of adsorbed layers. We report tests in which we measured the drain currents under high dc voltage of TFTR and JET accelerator insulators while they were successively exposed to vacuum, deuterium and tritium. There did not appear to be any substantial reduction in hold-off capability with tritium, although at some voltages there was a small increase in the leakage current. We also compared the breakdown properties of a plastic tubing filled with deuterium and then tritium at varying pressures, since such tubing has been considered as a high-voltage break in the gas feed system for TFTR, and the presence of large numbers of electron-ion pairs might lead to enhanced Paschen breakdown. We found no significant differences in the behavior for the geometry used.
    Type of Medium: Electronic Resource
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