Fluorine in tourmalines     

Dušan Němec 《Contributions to Mineralogy and Petrology》1969,20(3):235-243

The determination of the fluorine content of courmalines yielded 0.28% as an average value for schorlites and dravites and 0.97% for elbaites. The plot of the fluorine contents against the lithium contents shows that the distribution of projection points for pink or green elbaites differs from that for lithian indigolites. Tourmalines are poorer in fluorine than lightcoloured micas at the same stage of pegmatite evolution. Individual regions with pegmatite occurrences can be characterized as rich or poor in fluorine according to the fluorine contents in the tourmalines and micas contained in the pegmatites.  相似文献   

便携式光电望远镜用于流星暴观测的探讨     

顾光德  余月花 《紫金山天文台台刊》1999,18(1):76-79

本文介绍了便携式人卫光电望远镜的主要性能特点,探讨了将其应用于狮子座流星暴观测的可能性。  相似文献   

Kinetic study of the hydrocarbon generation from Upper Paleozoic coals in Ordos Basin   总被引：6，自引：0，他引：6  

付少英  彭平安  张文正  刘金钟  李剑峰  昝川莉 《中国科学D辑(英文版)》2003,46(4):333-341

When organic matter during geological processes is affected by a variety of factors such as paleotemperature, and time, complicated chemical reactions will occur, finally resulting in the generation of petroleum and natural gas. These reactions leading to…  相似文献   

Characteristics of melt inclusions in skarn minerals from Fe,Cu(Au) and Au(Cu) ore deposits in the region from Daye to Jiujiang   总被引：5，自引：0，他引：5  

赵斌  赵劲松  李兆麟  张重泽  彭卓伦 《中国科学D辑(英文版)》2003,46(5):481-497

The skarns and skarn deposits are widely distributed at home and abroad. The skarn deposits include many kinds of ores and higher ore grade. Some of them are broad in scale. Scientists of ore deposits from different countries have paid and are paying grea…  相似文献   

近44 a中国冬夏气温变率及其对区域变暖性的影响   总被引：6，自引：2，他引：4  

吴胜安  江志红  屠其璞 《南京气象学院学报》2002,25(6):830-836

利用近44a中国85个测站冬夏季逐日平均、最高和最低气温序列,研究冬夏季温度季节变率及其时空演变特征,探讨其对区域变暖稳定性的影响。结果表明：冬季,除高原、西南、东北以外的中国大部分地区,温度的季节变率存在显著下降趋势,是近期变暖的稳定区,其中变暖最为稳定、显著的区域是西北、华北地区,东北北部虽变暖幅度很大,但稳定性最差;夏季,长江中下游及其江南地区温度变率存在显著上升趋势,20世纪70年代后年际变幅明显增大,表明该地区80年代降温的稳定性差。  相似文献   

Recent Progress in the Impact of the Tibetan Plateau on Climate in China   总被引：14，自引：0，他引：14  

刘屹岷  包庆  段安民  钱正安  吴国雄 《大气科学进展》2007,24(6):1060-1076

Studies of the impacts of the Tibetan Plateau （TP） on climate in China in the last four years are reviewed. It is reported that temperature and precipitation over the TP have increased during recent decades. From satellite data analysis, it is demonstrated that most of the precipitation over the TP is from deep convection clouds. Moreover, the huge TP mechanical forcing and extraordinary elevated thermal forcing impose remarkable impacts upon local circulation and global climate. In winter and spring, stream flow is deflected by a large obstacle and appears as an asymmetric dipole, making East Asia much colder than mid Asia in winter and forming persistent rainfall in late winter and early spring over South China. In late spring, TP heating contributes to the establishment and intensification of the South Asian high and the abrupt seasonal transition of the surrounding circulations. In summer, TP heating in conjunction with the TP air pump cause the deviating stream field to resemble a cyclonic spiral, converging towards and rising over the TP. Therefore, the prominent Asian monsoon climate over East Asia and the dry climate over mid Asia in summer are forced by both TP local forcing and Eurasian continental forcing.
Due to the longer memory of snow and soil moisture, the TP thermal status both in summer and in late winter and spring can influence the variation of Eastern Asian summer rainfall. A combined index using both snow cover over the TP and the ENSO index in winter shows a better seasonal forecast.
On the other hand, strong sensible heating over the Tibetan Plateau in spring contributes significantly to anchor the earliest Asian monsoon being over the eastern Bay of Bengal （BOB） and the western Indochina peninsula. Qualitative prediction of the BOB monsoon onset was attempted by using the sign of meridional temperature gradient in March in the upper troposphere, or at 400 hPa over the TP. It is also demonstrated by a numerical experiment and theoretical study that the heating over the TP lea  相似文献   

Zur Frage der Geoelektrischen Blitzgefährdung     

Hon.-Doz. Dr. Volker Fritsch 《Pure and Applied Geophysics》1956,35(1):149-160

Zusammenfassung Der Verfasser untersucht das Problem, ob die Einschlagstelle des Blitzes auch durch die geoelektrische Bodenbeschaffenheit mitbestimmt ist. Zur Untersuchung dieser Frage wurden bisher Modellversuche, mathematische Berechnungen und Auswertungen der Statistik herangezogen. Der Verfasser kommt durch die Auswertung einer umfangreichen Blitzschlagstatistik, die für österreich angelegt wurde, zu dem Ergebnis, dass es ausgedehnte Gebiete gibt, die wegen ihrer besonderen geoelektrischen Bodenbeschaffenheit stark blitzgefährdet sind und dass auch begrenzte Zonen dieser Art, die sogenannten « Blitznester » existieren.

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Summary The author investigates the problem whether certain places of the ground are especially often struck by lightning and whether this effect is caused by the geoelectrical nature of the underground. By examining a great number of results obtained in Austria the author comes to the solution that the question of the existance of the so-called « lightning nests » must be answered in the affirmative.

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Aus einem Referat auf dem 4. Internationalen Blitzschutzkongress 1956 in Meran.  相似文献   

西北干旱区夏季强干、湿事件降水环流及水汽输送的再分析   总被引：4，自引：0，他引：4  

蔡英  宋敏红  钱正安  吴统文  栾晨 《高原气象》2015,(3):597-610

为深入分析西北内陆干旱区夏季降水的主要水汽源地及其输送通道,首先,梳理和评述了过去50年西北干旱区水汽输送的研究进展和问题;接着,利用国家气象局信息中心近50年的实测降水及NCEP/NCAR再分析资料等,挑选更多有代表性的强干、湿日(月)事件,再进行环流和水汽输送的对比分析。主要结论如下:(1)过去西北干旱区各地的干、湿环流研究共识多,进展快;而水汽输送分析依旧众说纷纭。(2)过去的水汽输送分析联系降水环流不够;针对西北干旱区降水特点不够;还应加进数值模拟等分析手段。(3)在本文诊断分析和先前数值模拟基础上,指出西北内陆旱区夏季降水的主要水汽源地在东南沿海一带,它借助西行台风、西伸了的西太平洋副热带高压及柴达木低压等多个天气系统和西太平洋副热带高压西南侧东南风急流、西侧南风低空急流及河西偏东风等三支气流的次第密切配合,首先,水汽被输送到四川盆地;接着,被北输到西北区东部;继而,再被接力西输到河西走廊及南疆盆地东部。谓之"三支气流+两个中转站的三棒接力"式水汽输送模型。它是夏季输向西北内陆旱区的主要水汽输送通道。  相似文献   

Asteroseismic modelling of the solar-like star β Hydri     

G. Doğan  I. M. Brandão  T. R. Bedding  J. Christensen-Dalsgaard  M. S. Cunha  H. Kjeldsen 《Astrophysics and Space Science》2010,328(1-2):101-104

We present the results of modelling the subgiant star β Hydri using seismic observational constraints. We have computed several grids of stellar evolutionary tracks using the Aarhus STellar Evolution Code (ASTEC, Christensen-Dalsgaard in Astrophys. Space Sci. 316:13, 2008a), with and without helium diffusion and settling. For those models on each track that are located at the observationally determined position of β Hydri in the Hertzsprung-Russell (HR) diagram, we have calculated the oscillation frequencies using the Aarhus adiabatic pulsation package (ADIPLS, Christensen-Dalsgaard in Astrophys. Space Sci. 316:113, 2008b). Applying the near-surface corrections to the calculated frequencies using the empirical law presented by Kjeldsen et al. (Astrophys. J. 683:L175, 2008), we have compared the corrected model frequencies with the observed frequencies of the star. We show that after correcting the frequencies for the near-surface effects, we have a fairly good fit for both l=0 and l=2 frequencies. We also have good agreement between the observed and calculated l=1 mode frequencies, although there is room for improvement in order to fit all the observed mixed modes simultaneously.  相似文献   

南海神狐海域水合物三相混合层测井评价方法研究     

谢莹峰  陆敬安  匡增桂  康冬菊  王通  蔡慧敏 《现代地质》2022,36(1):182-192

天然气水合物降压试采过程中,水合物、游离气和水的三相混合层中的游离气首先被采出,从而提高降压效率,促进水合物分解;因此利用岩心刻度测井的方法开展南海神狐海域水合物三相混合层测井评价方法研究,对水合物矿体储量计算以及产业化开采具有重要意义.三相混合层与水合物层相比,其密度和中子孔隙度值均减小,纵波速度明显下降;与气层相比...  相似文献