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991.
Summary All of the barium and marginal barium stars in the 1972 MacConnell, Frey, and Upgren (1972: MFU) list of such objects which
are located south of the celestial equator were examined for visual duplicity. Over 200 objects were observed, and a total
of six possible candidates for wide pair visual binaries were found. Of these, four are most likely optical in nature. These
data suggest that the incidence of wide binaries among barium stars is of the order of 1%. 相似文献
992.
We have reported the discovery of a population of the normal extragalactic field galaxies with the clear presence of strong
FHIL (forbidden high by ionized lines) and HeII 4686 emission. In this paper we present a dozen of them extracted from the
SDSS dr7. The high resolution spectra 0.86 ? /px obtained with the 6-m telescope of the Special Astrophysical observatory
of Russia are introduced for one of them, SDSS J093801.63 + 135317.0 confirming the presence of strong and wide FHIL and HeII
4686 emission. These objects show typical narrow (FWHM ~ 120 - 250 km s-1) emission lines both of HI and forbidden emission lines of [NII] 6548/84, [SII] 6717/31, [OI] 6300, [OII] 3727, and [OIII]
5007/4959 with underlying stellar absorption lines, coupled with the strong FHIL emission of [FeVII] 5721, 6087, [FeX] 6375,
[FeXI] 7892, [FeXIV] 5303, and HeII 4686, sometimes very broad up to 1500 km s-1. Following the direct images, all morphological types are introduced, spherical, elliptical, spiral, barred spiral, etc.,
without morphological or other peculiarity and any signs of "standard" AGN activity. None of them are X-ray source. The appearance
of the FHIL emission in normal galaxies (the objects of SBN/HII/ELG spectral types) might be one of the important sign of
the beginning of the AGN activity. The existence of the numerous normal extragalactic objects with FHIL and HeII 4686 emission
tell us that the link between the AGNs and the normal galaxies perhaps might be realized with the FHIL flare in normal galaxies.
For all of them, the existence of the nonthermal source in normal galaxies should be proposed. 相似文献
993.
994.
995.
The results of the electromagnetic studies, obtained on the North Pole drifting stations, are reviewed. These results are
still of current interest. The aspects of similar future works are discussed. 相似文献
996.
The present article is the second in a series of baseline water quality evaluation studies in parts of south-eastern Nigeria.
Study results indicate that the water samples from the study are generally acidic, soft and fresh in addition to low sodium
and salinity hazard. Regression equations indicate a good positive correlation between conductivity and Na, Ca, Mg and SO4. Ca-SO4 and Ca-Cl constitute the major facies in the area. Generally the waters in the area are good for most domestic and agricultural
purposes.
Received: 14 April 1997 · Accepted: 3 February 1998 相似文献
997.
The geochemical study of the suspended matter in the waters of the Amazon River and its tributaries revealed that the chemical composition of this material ranges widely; however, generally, it is similar to the average composition of the suspended matter in the rivers and clayey sedimentary rocks around the world. Against this background, an essential regional Hg enrichment due to the anthropogenic factor is distinguished. The suspensions from the so-called clear waters from the tributaries of the Amazon River—Xingu and Trombetas—demonstrate the local enrichment in Pb, Sn, Zn, and organic carbon indicating the ore mineralization of the drainage basin, and points to the presence of metal-organic complexes. 相似文献
998.
X.Z. Zhang S.J. Qian L.A. Higgs T.L. Landecker X.J. Wu 《Astrophysics and Space Science》2002,279(4):355-366
Radio observational results at 232 MHz and multifrequency studies of supernova remnant (SNR) HB21 are presented. Its integrated
flux density at 232 MHz is about 390 ± 30 Jy. Both the integrated spectral index and the spatial variations of spectral index
of the remnant were calculated by combining the new map at 232 MHz with previously published maps made at 408, 1420, 2695,
and 4750 MHz. The SNR has an integrated spectral index of about α = -0.43(S
ν ∝ να) between 232 and 4750 MHz. In general the spectral index varies from –0.5 in southeast and west regions of the remnant to
–0.3 in the central region and near the northwest edge. The new data of 232 MHz reveals that there is interaction between
the remnant and the surrounding gas along the east edge of the remnant which causes the spectrum flattening at low frequency,
while the very good agreement between the structure of X-ray emission and the central flat spectrum area suggests that the
existence of thermal emission is the reason of spectrum flattening in the area.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
999.
The physicomathematical features of the plasma explosion region dynamics at altitudes higher than 100 km at the early stage of its development, which culminates in the transfer of a considerable portion of the initial plasma energy into the environment, are discussed in the first part of the work. The radiation gas dynamic, inertial, and shock stages of the disturbed region development are calculated. 相似文献
1000.
MERLIN and VLA observations of the galaxy M82 have detected a jet-like feature emanating from one of the compact sources, 44.01+59.6. The proximity of this source to the dynamical centre of M82 led us to suspect that it could be a weak active nucleus rather than an SNR. We imaged this source using the EVN at 15 mas and although it shows a compact shell-like structure which could be consistent with an SNR, we note that the EVN image shows a bright region within the source which is elongated along the jet direction. There are distinct similarities between this source and the Sgr A complex at the centre of our own Galaxy which contains the compact AGN, Sgr A*. 相似文献