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231.
232.
I. V. Pekov N. V. Chukanov N. N. Kononkova N. V. Zubkova M. Kh. Rabadanov D. Yu. Pushcharovsky 《Geology of Ore Deposits》2008,50(8):749-754
Elpasolite, K2NaAlF6, has been found for the first time in a pegmatite related to peralkaline foid syenite at Mt. Koashva, Khibiny alkaline pluton, Kola Peninsula, Russia, as pale pink octahedral crystals up to 2 mm in size within cavities in the natrolite core of pegmatite in association with amicite, sodalite, aegirine, pectolite, catapleiite, sitinakite, lemmleinite-K, and vinogradovite. The chemical composition determined with an electron microprobe is as follows, wt %: 31.53 K; 9.22 Na; 11.20 Al; 47.21 F; total is 99.16. The empirical formula is K1.96Na0.98Al1.01F6.05. The infrared spectrum is given. The crystal structure has been refined to R = 0.030, space group Fm $ \bar 3 Elpasolite, K2NaAlF6, has been found for the first time in a pegmatite related to peralkaline foid syenite at Mt. Koashva, Khibiny alkaline pluton,
Kola Peninsula, Russia, as pale pink octahedral crystals up to 2 mm in size within cavities in the natrolite core of pegmatite
in association with amicite, sodalite, aegirine, pectolite, catapleiite, sitinakite, lemmleinite-K, and vinogradovite. The
chemical composition determined with an electron microprobe is as follows, wt %: 31.53 K; 9.22 Na; 11.20 Al; 47.21 F; total
is 99.16. The empirical formula is K1.96Na0.98Al1.01F6.05. The infrared spectrum is given. The crystal structure has been refined to R = 0.030, space group Fm
m, a = 8.092 ?. The result of a special X-ray powder diffraction study confirmed the suggestion made by Morss (1974) that reflections
violating space group Fm
m in some published X-ray powder patterns of natural elpasolite are Kβ-lines.
Original Russian Text ? I.V. Pekov, N.V. Chukanov, N.N. Kononkova, N.V. Zubkova, M.Kh. Rabadanov, D.Yu. Pushcharovsky, 2007,
published in Zapiski Rossiiskogo Mineralogicheskogo Obshchestva, 2007, No. 6, pp. 76–84. 相似文献
233.
Agates are natural hierarchicalal structural assemblies composed largely of silica minerals: chalcedony, quartz, and quartzine. Microstructural heterogeneities, most typical of those of agate-forming minerals, are characterized by variations in periods of helicoidal twisting of chalcedony and by micrometric rhythmic alternation of zones with a low refractive index within the matrix of normal chalcedony, quartz, and quartzine. A study of the degree of crystallization of chalcedony using the Barsanova-Yakovleva method showed that neither helicoidal twisting nor refractive index zoning brought about any significant disturbance in the chalcedony structure. Helicoidal twisting is a result of the stresses caused by substitution of Si4+ for Al3+ asymmetric with respect to chalcedony crystal. It is suggested that layering by the refractive index developed due to accumulation of small portions of gel consisting of high silica polymers at the front of crystal growth. 相似文献
234.
V.B. Bazarova L.M. Mokhova M.A. Klimin L.A. Orlova K.Yu. Bazarov 《Russian Geology and Geophysics》2008,49(12):978-985
Climatic changes in southeastern Transbaikalia in the Middle and Late Holocene and their influence on alluvial sedimentation environments are reconstructed from the results of study of the Ilya floodplain sediments (Alkhanai National Park). At the beginning of the Subboreal period, the regional climate became more arid, which led to a significant increase in steppe species communities in the landscapes. Intense climate aridization also took place at the beginning and at the end of the Subatlantic period of the Holocene. The alluvial-sedimentation rate increased during the weakening of aridization and decreased during cooling and the intensification of aridization. The obtained regional data are compared with data on the adjacent areas and the global climatic changes in the Northern Hemisphere. 相似文献
235.
The methods of celestial mechanics can be used to construct a mathematical model for the perturbed rotational motions of the deformable Earth that can adequately describe the astrometric measurements of the International Earth Rotation Service (IERS). This model describes the gravitational and tidal influences of the Sun and Moon. Fine resonant interactions of long-period zonal tides (annual, semiannual, monthly, and biweekly) with the diurnal and semidiurnal tides are revealed. These interactions can be reliably confirmed via a spectral analysis of the IERS data. Numerical modeling of tidal irregularities of the Earth’s axial rotation was carried out, focusing on the analysis and forecasting of variations of the day length occurring within short time intervals of a year or shorter (intrayear variations). 相似文献
236.
基于复杂自适应系统理论,采用自下而上的基于智能体的建模分析方法,模拟了自然环境与钉螺生长相互作用导致的钉螺生长的主要行为特征、生命状态和数量变化,开发实现了模拟模型,同时输入实测数据进行实例模拟,结果表明该模型能够作为血吸虫病防控工作中钉螺数量估测的一种辅助实验方法和工具. 相似文献
237.
基于免疫多智能体的网络入侵主动防御模型 总被引:2,自引:0,他引:2
构建了一种基于免疫多智能体的网络入侵主动防御模型ADNIIMA(the active defense model for net-work intrusion based on immune multi-agent),提出免疫智能体概念,建立免疫智能体的逻辑结构及其运行机制,实现了对网络入侵的多层次、分布式主动防御机制,为网络安全保障提供一种新的思路. 相似文献
238.
239.
240.
本文在分析GPS RTK定位工作模式的基础上,以苏州市为研究对象,讨论了"多对多"模式GPS台站网系统设计,研究了相应的操作规程,并进行了该模式下的定位试验,对定位结果的精度进行了分析,最后给出了结论。 相似文献