Observations of the supernova SN1987L with the new Faint Object Spectrograph on the 4.2 m William Herschel Telescope     

Gillian Pearce  Bruce Patchett  Jeremy Allington-Smith  Ian Parry 《Astrophysics and Space Science》1988,150(2):267-271

We present the spectrum of the supernova SN1987L in NGC 2336 over the wavelength range 4000–9700 Å as recorded in one 500 s exposure on 20–21 October, 1987. This spectrum was taken using the new Faint Object Spectrograph on the 4.2 m William Herschel Telescope (WHT) at the Observatorio del Roque de los Muchachos.We conclude that SN1987L was a type Ia supernova, and approximately 100 days post maximum at the time of the observation.  相似文献   

Inversion of sonic waveforms with unknown source and receiver functions     

L. Neil Frazer  Xinhua Sun  Roy H. Wilkens 《Geophysical Journal International》1997,129(3):579-586

A seismogram that is several times the length of the source-receiver wavelet is windowed into two parts—these may overlap—to obtain two seismograms with approximately the same source function but different Green's functions. A similarly windowed synthetic seismogram gives two corresponding synthetic seismograms. The spectral product of the window 1 data with the window 2 synthetic is equal to the spectral product of the window 1 synthetic with the window 2 data only if the correct earth model is used to compute the synthetic. This partition principle is applied to well-log sonic waveform data from Ocean Drilling Project hole 806B, a slow formation, and used there to estimate Poisson's ratio from a single seismogram whose transmitter and receiver functions are unknown. A multichannel extension of the algorithm gives even better results. The effective borehole radius R _b, was included in the inversion procedure, because of waveform sensitivity to R _b. Inversion results for R _b agreed with the sonic caliper, but not the mechanical caliper; thus if R _b is not included in the inversion its value should be taken from the sonic caliper.  相似文献   

A Compilation of New and Published Major and Trace Element Data for NIST SRM 610 and NIST SRM 612 Glass Reference Materials   总被引：37，自引：0，他引：37  

Nicholas J.G. Pearce  William T. Perkins  John A. Westgate  Michael P. Gorton  Simon E. Jackson  Clive R. Neal  Simon P. Chenery 《Geostandards and Geoanalytical Research》1997,21(1):115-144

Microanalytical trace element techniques (such as ion probe or laser ablation ICP-MS) are hampered by a lack of well characterized, homogeneous standards. Two silicate glass reference materials produced by National Institute of Standards and Technology (NIST), NIST SRM 610 and NIST SRM 612, have been shown to be homogeneous and are spiked with up to sixty one trace elements at nominal concentrations of 500 μg g-1 and 50 μg g-1 respectively. These samples (supplied as 3 mm wafers) are equivalent to NIST SRM 611 and NIST SRM 613 respectively (which are supplied as 1 mm wafers) and are becoming more widely used as potential microanalytical reference materials. NIST however, only certifies up to eight elements in these glasses. Here we have compiled concentration data from approximately sixty published works for both glasses, and have produced new analyses from our laboratories. Compilations are presented for the matrix composition of these glasses and for fifty eight trace elements. The trace element data includes all available new and published data, and summaries present the overall average and standard deviation, the range, median, geometric mean and a preferred average (which excludes all data outside ± one standard deviation of the overall average). For the elements which have been certified, there is a good agreement between the compiled averages and the NIST data. This compilation is designed to provide useful new working values for these reference materials.  相似文献   

Primary cumulus platinum minerals in the Monts de Cristal Complex,Gabon: magmatic microenvironments inferred from high-definition X-ray fluorescence microscopy     

Stephen J. Barnes  Louise A. Fisher  Bélinda Godel  Mark A. Pearce  Wolfgang D. Maier  David Paterson  Daryl L. Howard  Christopher G. Ryan  Jamie S. Laird 《Contributions to Mineralogy and Petrology》2016,171(3):23

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The UBV orbital phase curves of Rhea,Dione, and Tethys     

Guy N. Blair  Frazer N. Owen 《Icarus》1974,22(2):224-229

Orbital phase curves are reported for Rhea (SV), Dione (SIV), and Tethys (SIII). Variations of 0.2 mag. and 0.8 mag. were found for Rhea and Dione respectively, while no variation of Tethys was detected. Some color variations are also reported.  相似文献   

Evald Rudolfovich Mustel     

G. Pearce  A. J. Mayes 《Astrophysics and Space Science》1989,155(1):vi-1

In Memoriam

Evald Rudolfovich Mustel1911–1988  相似文献   

The baryon fraction of ΛCDM haloes     

Robert A. Crain  Vincent R. Eke  Carlos S. Frenk  Adrian Jenkins  Ian G. McCarthy  Julio F. Navarro  Frazer R. Pearce 《Monthly notices of the Royal Astronomical Society》2007,377(1):41-49

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Tephrostratigraphy and glass compositions of post-15 kyr Campi Flegrei eruptions: implications for eruption history and chronostratigraphic markers     

V.C. Smith  R. Isaia  N.J.G. Pearce 《Quaternary Science Reviews》2011,30(25-26):3638-3660

Volcanic ash (tephra) erupted from the frequently active Campi Flegrei volcano forms layers in many palaeoenvironmental archives across Italy and the Mediterranean. Proximal deposits of 50 of the post-15 ka eruptions have been thoroughly sampled and analysed to produce a complete database of glass compositions (>1900 analyses) to aid identification of these units. The deposits of individual eruptions are compositionally diverse and this variability is often greater than that observed between different units. Many of the tephra units do not have a unique glass chemistry, with compositionally similar tephra often erupted over long periods of time (1000s years). Thus, glass chemistry alone is not enough to robustly correlate most of the tephra from Campi Flegrei, especially in the last 10 kyrs. In order to reliably correlate the eruption units it is important to take into account the stratigraphy, chronology, magnitude, and dispersal of the eruptions, which has been collated to aid identification. An updated chronology is also presented, which was constrained using Bayesian analysis (OxCal) of published radiocarbon dates and ⁴⁰Ar/³⁹Ar ages. All the data presented can be employed to help correlate post-15 ka tephra units preserved in archaeological and Holocene palaeoenvironmental archives. The new database of proximal glass compositions has been used to correlate proximal volcanic deposits through to distal tephra layers in the Lago di Monticchio record (Wulf et al., 2004, Wulf et al., 2008) and these correlations provide information on eruption stratigraphy and the tempo of volcanism at Campi Flegrei.  相似文献   

A sonar model for humpback whale song     

Frazer  L.N. Mercado  E.  III 《Oceanic Engineering, IEEE Journal of》2000,25(1):160-182

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Estimating the diffuse attenuation coefficient from optically active constituents in UK marine waters   总被引：1，自引：0，他引：1  

M.J. Devlin  J. Barry  D.K. Mills  R.J. Gowen  J. Foden  D. Sivyer  N. Greenwood  D. Pearce  P. Tett 《Estuarine, Coastal and Shelf Science》2009

We report a study of the attenuation of submarine Photosynthetically Active Radiation (PAR) in relation to the concentrations of Optically Active Constituents (OACs) in a range of water types around the United Kingdom. 408 locations were visited between August 2004 and December 2005. The diffuse attenuation coefficient (K_d) was estimated from profiles of downwelling PAR. Concentrations of Suspended Particulate Matter (SPM) were measured gravimetrically and concentrations of phytoplankton chlorophyll (chl) were measured by fluorometrically. Chromophoric Dissolved Organic Matter (CDOM) was measured either by fluorescence or as its proxy, salinity.  相似文献