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831.
N. J. C. Spooner G. J. Davies C. H. Lally N. J. T. Smith M. van den Putte P. F. Smith J. D. Lewin G. T. A. Squier P. Jagpal 《Astroparticle Physics》1996,5(3-4):299-307
The UVIS dark matter detector, proposed by Spooner and Smith (Phys. Lett. B 314 (1993) 430), consists of < 1000 ppm Tl doped NaI scintillator operated at 100-200 K, with measurement of UV and visible scintillation components used to discriminate between electrons (gammas) and Na or I recoils. Presented here are results of measurements of the gamma/nuclear recoil discrimination power of a Kyropolous NaI (0.5 ppm Tl) UVIS test detector operated at 160 K, with monoenergetic neutrons used to induce nuclear recoils via elastic scattering. Defining the statistical gain factor for N events as
, the coefficient Cm was measured as a function of photoelectron pulse height. At 40 photoelectrons Cm was found to be 0.5 (corresponding to 90% rejection of gammas with 20% loss of neutron events). The scintillation efficiency for Na and I recoils relative to electrons was also measured at 160 K and found to be 35 ± 5% for Na recoils and 10 ± 2% for iodine. 相似文献
832.
Bockelée-Morvan D. Wink J. Despois D. Colom P. Biver N. Crovisier J. Gautier D. Gérard E. Lellouch E. Moreno R. Paubert G. Rauer H. Davies J. K. Dent W. R. F. 《Earth, Moon, and Planets》1997,78(1-3):67-67
Spectroscopic observations of comet Hale-Boppwere undertaken near perihelion at millimetre wavelengths with the Institut de
Radioastronomie Millimétrique (IRAM) telescopes at Plateau de Bure (France)and Pico Veleta (Spain). They resulted in the first
detections of HCOOH,SO2, NH2CHO and HCOOCH3 in a comet. HDO was detected through its312–221 line at 225.897 GHz,complementing the observation of the 101–000 line at 464.925 GHz at the James Clerk Maxwell Telescope (Meier et al., 1998,Science 279, 842).Several unidentified lines
are present in the spectra. Observations of HC3N, HNCO, OCS, SO, CN, CO+, HCO+, in addition to more ‘classical’species CO, HCN, HNC, CH3CN, CH3OH, H2CO, CS and H2S (Biveret al., this issue) permit us to make out an extensive inventory of the composition of the coma of comet Hale-Bopp
at its perihelion. It presents strong analogies with gas-phase abundances measured in interstellar hot cores and bipolar flows,
which are believed to reflect the composition of interstellar grains.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
833.
M. E. Davies V. K. Abalakin M. Bursa J. H. Lieske B. Morando D. Morrison P. K. Seidelmann A. T. Sinclair B. Yallop Y. S. Tjuflin 《Celestial Mechanics and Dynamical Astronomy》1995,63(2):127-148
Every three years the IAU/IAG/COSPAR Working Group on Cartographic Coordinates and Rotational Elements of the Planets and Stallites revises tables giving the directions of the north poles of rotation and the prime meridians of the planets, satellites, and asteroids. Also presented are revised tables giving their sizes and shapes. 相似文献
834.
Michele Cappellari Eric Emsellem R. Bacon M. Bureau Roger L. Davies P. T. de Zeeuw Jesús Falcón-Barroso Davor Krajnovi Harald Kuntschner Richard M. McDermid Reynier F. Peletier Marc Sarzi Remco C. E. van den Bosch Glenn van de Ven † 《Monthly notices of the Royal Astronomical Society》2007,379(2):418-444
835.
836.
837.
Tim Adams Melvyn B. Davies Richard F. Jameson Aylwyn Scally 《Monthly notices of the Royal Astronomical Society》2002,333(3):547-560
We present the results of multiple simulations of open clusters, modelling the dynamics of a population of brown dwarf members. We consider the effects of a large range of primordial binary populations, including the possibilities of having brown dwarf members contained within a binary system. We also examine the effects of various cluster diameters and masses. Our examination of a population of wide binary systems containing brown dwarfs, reveals evidence for exchange reactions whereby the brown dwarf is ejected from the system and replaced by a heavier main-sequence star. We find that there exists the possibility of hiding a large fraction of the brown dwarfs contained within the primordial binary population. We conclude that it is probable that the majority of brown dwarfs are contained within primordial binary systems which then hides a large proportion of them from detection. 相似文献
838.
Melvyn B. Davies Steinn Sigurdsson 《Monthly notices of the Royal Astronomical Society》2001,324(3):612-616
We consider the survivability of planetary systems in the globular cluster 47 Tucanae. We compute the cross-sections for the breakup of planetary systems via encounters with single stars and binaries. We also compute the cross-sections to leave planets on eccentric orbits. We find that wider planetary systems ( d ≳0.3 au) are likely to be broken up in the central regions of 47 Tucanae (within the half-mass radius of the cluster). However, tighter systems and those in less-dense regions may survive. Tight systems will certainly survive in less-dense clusters where subsequent surveys should be conducted. 相似文献
839.
840.
Baris Anna Spacagna Rose Line Paolella Luca Koseki Junichi Modoni Giuseppe 《Bulletin of Earthquake Engineering》2021,19(10):3963-3986
Bulletin of Earthquake Engineering - The damage on supply and drainage water networks is a serious cause of economic disruption for urban systems affected by earthquakes. Among various concerns,... 相似文献