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991.
Studies on aggregate formation and size distribution in relation to bottom water composition and flow regime were carried out in November 1994 at two transects in the inner and outer Mecklenburg Bight (Baltic Sea). The bottom water sampler ‘BIOPROBE' (BWS) was used to collect 10-dm3 water samples at 5, 10, 20 and 40 cm above the seabed. The outer transect samples tended to be more influenced by the open western Baltic Sea, whereas the inner transect samples were more affected by the coastal hydrography. Aggregate size distribution was investigated using a newly developed particle camera allowing identification of particles down to 150 μm size. Increasing concentrations of total particulate matter (TPM), particulate organic carbon (POC) and chlorophyll pigment equivalents (CPE) towards the seafloor together with a low proportion of POC/TPM (<5%) implied that the material was of resuspended origin. Aggregate size in both transects was positively correlated with TPM, transparent exopolymer particles (TEP) and bacterial cell abundance. Higher particle concentrations and aggregate numbers in the outer transect indicated a higher resuspension frequency, or lateral advection processes. The higher concentration of aggregates at the outer transect may reflect the larger amount of near-bottom transported material. 相似文献
992.
The cometary Leonid meteoroids represent a size range in between largest carbon-richIDPs and the smallest CI meteorites. Their
dustball structure and chemistry offer anopportunity to constrain hierarchical dust accretion inferred from petrologic studies
ofaggregate and cluster IDPs. The Leonid shower meteoroids of known ``comet ejection'ages provide an opportunity to study
space weathering of cometary dust over periodsof up to several hundred years. The meteors and aggregate and cluster IDPs displaycontinuous
thermal modification of organics and volatile element (Na, K-bearing phases), that occur as discrete minerals and amorphous
solids each different response during kinetically controlled ablation. Leonid meteoroids are not excessively Na-rich. The
occurrences of Leonid meteors can now be accurate predicted and combined withknowledge better models for the settling rates,
collections of surviving dust becomea comet nucleus-sampling mission.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
993.
The experiment with 10K-80 aboard the INTER-BALL-2 (which detects protons with energies &gt; 7, 27&#x2013;41, 41&#x2013;58,
58&#x2013;88, 88&#x2013;180 and 180&#x2013;300 MeV) registered six events of the solar energetic particle (SEP)
increase. These events are during the initial rise phase of the 23rd solar activity cycle. Solar flares with the SEP generation
are accompanied by coronal mass ejection (CME). Here we analyze the dynamics of the differential energy spectrum at different
phases of the SEP increase. 相似文献
994.
贵州织金新华含稀土磷矿床扫描电镜研究 总被引:27,自引:1,他引:26
用扫描电子显微镜和X射线能谱仪等方法研究织金新华含稀土磷矿床矿物组成,结构特征及微量元素含量变化特征。通过EDAX能谱仪进行矿物成分分析,得出Y2O3质量分烽与胶磷矿物密切相关的结论。对伴生矿物作了相关研究,初步探讨了稀土元素赋存状态及富集规律。 相似文献
995.
996.
For the first time during the mission, the Anisotropy Telescopes instrument on board the Ulysses spacecraft measured constant zero anisotropy of protons in the 1.3/2.2 MeV energy range, for a period lasting more than three days. This measurement was made during the energetic particle event taking place at Ulysses between 25 November and 15 December 1998, an event characterised by constant high proton fluxes within a region delimited by two interplanetary forward shocks, at a distance of 5.2 AU from the Sun and heliographic latitude of 17°S. We present the ATs results for this event and discuss their possible interpretation and their relevance to the issue of intercalibration of the two telescopes. 相似文献
997.
The coupled ionosphere–thermosphere–plasmasphere system is very complex. The study of its interrelationships during geomagnetically disturbed conditions is an especially challenging task.Significant progress has been achieved during the last few years in developing comprehensive theoretical models to describe its global behaviour.Moreover, more simple, specialized numerical modelling of some specialaspects of storm behaviour and/or regional models have contributedto the progress in this field.This paper summarizes recent developments in upper ionosphereand plasmasphere storm studies and modelling.From an observational point of view the upper ionosphere/plasmasphereregion is well reflected in radio beacon measurements providing the totalelectron content (TEC). The development of space-based radio navigation systems such as GPS offersnew opportunities to derive TEC on both regional and global scale.Combining TEC with ionosonde data enables the variability of the shape of the electron density distribution during storms to be studied.We present some examples of co-ordinated investigation,made during the CEDAR storm study intervals. 相似文献
998.
The ISOCAM detector is subjected to transient effects induced bycosmic rays, the so-called glitches. This paper is focused onthe ISOCAM long wave detector. The predicted glitch rates havebeen re-evaluated by taking into account secondary particlesproduction in the materials surrounding the LW detector. We showin this preliminary study that the difference between thepreviously predicted glitch rate and the observed rate may beexplained by secondary particles. 相似文献
999.
A new electroluminescence device is fabricated by microwave plasma chemical vapour deposition system and electron beam vapour deposition system. It is comprised of highly doped silicon/diamond/boron/nitrogen-doped diamond/indium tin oxide thin films. Effects of process parameters on morphologies and structures of the thin films are detected and analysed by scanning electron microscopy, Raman spectrometer and x-ray photoelectron spectrometer. A direct-current (DC) power supply is used to drive the electroluminescence device. The blue light emission with a luminance of 1.2 cd·m- 2 is observed from this double-doped diamond thin film electroluminescence device at an applied voltage of 105 V. 相似文献
1000.
Analysis of the bias between TOPEX and GPS vTEC determinations 总被引:4,自引:2,他引:2
The TOPEX/Poseidon satellite was jointly developed and deployed by the National Aeronautics and Space Administration (NASA),
USA, and the Centre National d’Etudes Spatiales (CNES), France (for details see Chelton et al. In: Fu L-L, Cazenave A (eds)
International geophysics series, vol 69, ISBN 0-12-269545-3, Academic Press, CA, pp 1–131, 2001), with the main scientific
goal of sea surface height monitoring. The process that ends with the TOPEX main observable (the range between the satellite
and the sea surface) involves the measurement of several parameters of the radar pulses reflected by the sea surface and the
computation of several other corrections. After several calibration campaigns performed by the Calibration/Validation team
of the mission, it was found that TOPEX range determinations were systematically shorter than expected and it was decided
to add an empirical correction of +15 mm to the TOPEX range-computation algorithm. As a by-product, TOPEX provides vertical
total electron content (vTEC) determinations which have turned out to be a very important data source for the ionospheric
research community. Since TOPEX vTEC measurements became available, several comparison studies have detected a constant bias,
from +2 to +5 TECu, when TOPEX is compared to other vTEC sources, e.g., Global Positioning System (GPS), Doppler Orbitography
and Radio-positioning Integrated by Satellite (DORIS), (TOPEX always greater than the others). In this work, we show that
miscalibration of the corrections used in the TOPEX processing algorithm can cause the shortening effect of TOPEX ranges and
at the same time the constant bias on the TOPEX vTEC values. It is also shown that changes on TOPEX System Biases of less
than 10 mm for the Ku-band and between 40 and 70 mm for the C-band, can make both effects disappear. The analyzed hypothesis
is supported by theoretical considerations and data analysis available in the specialized literature.
On behalf of the authors of the contribution ‘Analysis of the bias between TOPEX and GPS vTEC determinations’, I declare that
the paper has not been, nor is in the process of being published in any other publication. 相似文献