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Irakli Simonia 《Astrophysics and Space Science》2011,332(1):91-98
Investigations of the luminescence of frozen hydrocarbon particles of icy cometary halo have been made. The process of luminescence
of icy particles in shortwavelength solar radiation field is considered. The comparative analysis of observed and laboratory
data leads of 72 luminescent emission lines in the spectrum of 153P/Ikeya-Zhang comet. Several aspects of the problem are
discussed. 相似文献
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Arnold Gucsik Taro Endo Hirotsugu Nishido Kiyotaka Ninagawa Masahiro Kayama Szaniszló Bérczi Szabolcs Nagy Péter Ábrahám Yuki Kimura Hitoshi Miura Ildikó Gyollai Irakli Simonia Péter Rózsa József Posta Dániel Apai Krisztián Mihályi Mihály Nagy Ulrich Ott 《Meteoritics & planetary science》2013,48(12):2577-2596
Highly forsteritic olivine (Fo: 99.2–99.7) in the Kaba meteorite emits bright cathodoluminescence (CL). CL spectra of red luminescent forsterite grains have two broad emission bands at approximately 630 nm (impurity center of divalent Mn ions) in the red region and above 700 nm (trivalent Cr ions) in the red–IR region. The cores of the grains show CL blue luminescence giving a characteristic broad band emission at 400 nm, also associated with minor red emissions related to Mn and Cr ions. CL color variation of Kaba forsterite is attributed to structural defects. Electron probe microanalyzer (EPMA) analysis shows concentrations of Ca, Al, and Ti in the center of the forsterite grain. The migration of diffusible ions of Mn, Cr, and Fe to the rim of the Kaba meteoritic forsterite was controlled by the hydrothermal alteration at relatively low temperature (estimated at about 250 °C), while Ca and Al ions might still lie in the core. A very unusual phase of FeO (wüstite) was also observed, which may be a terrestrial alteration product of FeNi‐metal. 相似文献
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Ground motion prediction equations based on shallow crustal earthquakes in Georgia and the surrounding Caucasus 下载免费PDF全文
Jorjiashvili Nato Shengelia Ia Godoladze Tea Gunia Irakli Akubardia Dimitri 《地震科学(英文版)》2022,35(6):497-509
Strong ground motions caused by earthquakes with magnitudes ranging from 3.5 to 6.9 and hypocentral distances of up to 300 km were recorded by local broadband stations and three-component accelerograms within Georgia’s enhanced digital seismic network. Such data mixing is particularly effective in areas where strong ground motion data are lacking. The data were used to produce models based on ground-motion prediction equations (GMPEs), one benefit of which is that they take into consideration information from waveforms across a wide range of frequencies. In this study, models were developed to predict ground motions for peak ground acceleration and 5%-damped pseudo-absolute-acceleration spectra for periods between 0.01 and 10 s. Short-period ground motions decayed faster than long-period motions, though decay was still in the order of approximately 1/r. Faulting mechanisms and local soil conditions greatly influence GMPEs. The spectral acceleration (SA) of thrust faults was higher than that for either strike-slip or normal faults but the influence of strike-slip faulting on SA was slightly greater than that for normal faults. Soft soils also caused significantly more amplification than rocky sites. 相似文献
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Irakli S. Nanobashvili 《Astrophysics and Space Science》2004,294(3-4):125-134
Plasma mechanism for the generation of toroidal magnetic field in the magnetosphere of Crab pulsar is presented. The mechanism
is based on the development of parametric type instability in the relativistic electron-positron plasma of the pulsar magnetosphere.
As a result of plasma corotation with pulsar and its magnetic field, the effect of plasma radial braking takes place and the
time dependence of plasma particle radial velocity is harmonic. This triggers the development of parametric type instability
in the relativistic plasma of the pulsar magnetosphere. The energy for this process is drawn from the slowing down of pulsar
rotation. 相似文献
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Irakli Simonia 《Journal of Astrophysics and Astronomy》2005,26(4):421-427
The possible nature of unidentified cometary emissions is under discussion. We propose a new model of the ice particles in
cometary halos as a mixture of frozen polycyclic aromatic hydrocarbons and acyclic hydrocarbons. We describe principal properties
of frozen hydrocarbon particles (FHPs) and suggest interpreting some of the unidentified cometary emission lines as the photoluminescence
of FHPs. The results of comparative analysis are present. 相似文献
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