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21.
L. Sriramkumar 《General Relativity and Gravitation》2003,35(9):1699-1705
We consider the response of a uniformly accelerated monopole detector that is coupled to a superposition of an odd and an even power of a quantized, massless scalar field in flat spacetime in arbitrary dimensions. We show that, when the field is assumed to be in the Minkowski vacuum, the response of the detector is characterized by a Bose-Einstein factor in even spacetime dimensions, whereas a Bose-Einstein as well as a Fermi-Dirac factor appear in the detector response when the dimension of spacetime is odd. Moreover, we find that, it is possible to interpolate between the Bose-Einstein and the Fermi-Dirac distributions in odd spacetime dimensions by suitably adjusting the relative strengths of the detector's coupling to the odd and the even powers of the scalar field. We point out that the response of the detector is always thermal and we, finally, close by stressing the apparent nature of the appearance of the Fermi-Dirac factor in the detector response. 相似文献
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E. K. Sadykov V. V. Arinin G. I. Petrov A. V. Pyataev F. G. Vagizov O. A. Kocharovskaya 《Hyperfine Interactions》2006,167(1-3):893-896
The role of quantum interference (QI) in spectra of the resonant Mössbauer scattering is investigated. As a mechanism ensuring the QI conditions, the radio-frequency (RF) mixing of the spin sublevels of the excited nuclear state is considered. It is shown that QI leads to a significant intensity redistribution of the elastic and Raman scattering. 相似文献
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A method has been developed to determine the boiling point distribution of sulfur compounds in light cycle oils (LCO'S). The method chosen for this analysis was GC with a flame photometric detector (FPD) and pyrolyzer. Tests were carried out to evaluate the recovery efficiency, repeatability, and accuracy of the method. Repeatabilities within 2% were obtained. The recovery of benzothiophenes and dibenzothiophenes was close to 100%; this was important because these are the major sulfur components in LCO's. No hydrocarbon or solvent interferences were observed with the use of the pyrolyzer, even for a 95% solvent level. Comparison with results from other techniques showed that the method accurately determined the levels of sulfur compounds in the LCO boiling point range. 相似文献
27.
Nitro musks in cosmetic products—determination by headspace solid-phase microextraction and gas chromatography with atomic-emission detection 总被引:1,自引:0,他引:1
Summary The combination of headspace solid-phase microextraction with atomic-emission detection enables highly selective and sensitive
determination of itro musk compounds in cosmetic products. Sample preparation is considerably simplified; there is no solvent
extraction step. Enrichment is influenced by the type and amount of cosmetic product investigated. The lowest amount giving
well detectable peaks is 1 mg musk compound per kg sample. Calibration curves obtained from spiked solutions of selected reference
cosmetics in water show very good linearity. Relative standard deviations of peak areas from repeated measurements are usually
<10%.
Presented at the 21st ISC held in Stuttgart, Germany, 15th–20th September, 1996 相似文献
28.
Gamma ray bursts (GRBs) have been proposed as one possible class of sources of the ultrahigh energy cosmic ray (UHECR) events
observed up to energies ≳ 1020 eV. The synchrotron radiation of the highest energy protons accelerated within the GRB source should produce gamma rays up
to TeV energies. Here we briefly discuss the implications on the energetics of the GRB from the point of view of the detectability
of the prompt TeV γ-rays of proton-synchrotron origin in GRBs in the up-coming ICECUBE muon detector in the south pole. 相似文献
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S. Burachas S. Beloglovsky D. Elizarov I. Makov Yu. Saveliev N. Vassilieva M. Ippolitov V. Manko S. Nikulin A. Nyanin A. Vasiliev A. Apanasenko G. Tamulaitis 《Radiation measurements》2004,38(4-6):367-370
Technological conditions ensuring growth of optically homogeneous lead tungstate (PWO) crystals are reported. It is shown that the basic scintillator characteristics of PWO grown from highly purified raw material and properly doped with lanthanides are mainly determined by inclusions of oxides W1−yLyO3−x (L=Y, La, Gd; 0<x<0.3). Moreover, surface-located inclusions with structure close to tungstenite may also be of importance. It is demonstrated that the scintillation properties can be intentionally designed by varying the oxygen content in the inclusions x and the surface structure. The optimal value for x and the most favorable surface structure are achieved by proper thermal regimes and environment content during the crystal annealing. The results enabled low-cost fabrication of PWO scintillators with steady and reproducible characteristics acceptable for the CERN project ALICE and ensured production of PWO on an industrial scale by “North Crystals” company at a rate of 125–135 crystals per year from every growth apparatus. 相似文献