Use of Programs for Two-Parameter Multiple Impulse Correction of Altitude and Inclination of Circular Orbits     

A. E. Nazarov 《Solar System Research》2018,52(7):613-621

The paper describes the method for the development of programs for two-parameter multiple impulse correction of altitude and inclination of circular orbits. The considered corrections feature the simultaneous adjustment of altitude and inclination of the orbit under limited thrust of the propulsion system of the spacecraft. Low thrust-to-weight ratio of the spacecraft leads to the need for a correction program consisting of several burns of the propulsion system. Thrust vector orientation, burn time, and its operation duration are determined as propulsion system parameters.  相似文献   

Tropical cyclones in the Lesser Antilles: descriptive statistics and historical variability in cyclone energy, 1638–2009     

Michael Chenoweth  Dmitry Divine 《Climatic change》2012,113(3-4):583-598

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Eigen analysis of tree-ring records: part 3, taking heteroscedasticity and sampling effects into consideration     

Bao Yang  Dmitry M. Sonechkin  Nina M. Datsenko  Nadezda N. Ivashchenko  Jingjing Liu  Chun Qin 《Theoretical and Applied Climatology》2012,107(3-4):519-530

This paper reports on the further development of a new technique for standardization of tree-ring records called the eigen analysis of tree-ring records. The data are from the same sample set of 56 long-lived Qilian junipers (Sabina przewalskii Kom.) from the Dulan region in western China as was used in our previous paper (Yang et al. 2011b). To assess the heteroscedasticity of individual record deviations from the sample set regional curve (RC), we tested five different definitions of those deviations. Direct computations of eigenvectors of all relevant intrarecord covariation matrices turned out to be greatly affected by observational and computational noise; an analytic approximation of these vectors was therefore desirable. The Bessel function of the first kind and the zero order proved suitable for such an approximation, especially because the deviations were defined via subtraction of the RC from raw ring width records. Exclusion of the contributions of the first segment of the Bessel approximation, corresponding to the extremely large first eigenvalue, rendered individual record deviations from RC homoscedastic. Therefore, the routine Fourier basis became applicable to extract climate-dependent components of the residual deviations. A Fourier expansion of the Dulan chronology revealed the quasi-200-year-long solar activity cycle to be the main factor affecting Dulan tree growth.  相似文献   

激光剥蚀-等离子体质谱技术及其在地球化学宇宙化学和环境研究中的应用   总被引：1，自引：0，他引：1  

JOCHUM Klaus Peter  STOLL Brigitte  FRIEDRICH Jon M  AMINI Marghaleray  BECKER Stefan  DüCKING Marc  EBEL Denton S  ENZWEILER Jacinta  胡明月  KUZMIN Dmitry  MERTZ KRAUS Regina  MüLLER Werner E G  REGNERY Julia  SOBOLEV Alexander  王晓红  詹秀春 《岩矿测试》2009,28(1):53-68

激光剥蚀-等离子体质谱(LA-ICPMS)已成为地球化学、宇宙化学和环境研究领域元素和同位素原位分析最重要的技术之一。文章介绍了多种类型的质谱仪及其使用的激光器。用途最广的LA-ICPMS仪器之一是单接收器扇形磁场质谱仪,配有Nd:YAG激光剥蚀系统(激光波长分为193 nm和213 nm两种),MPI Mainz实验室使用的就是这套系统,文章对此作一详细介绍。文中阐述了数据优化技术及其多种校正过程;介绍LA-ICPMS在痕量元素和同位素分析领域的一些应用,包括参考物质的研制,Hawaiian玄武岩、Martian陨石、生物骨针和珊瑚虫中痕量元素分析及熔融包裹体和富钙-铝碳质球粒陨石中的铅和锶同位素测量。  相似文献   

Dynamics of fish catches in the eastern Gulf of Finland (Baltic Sea) and downstream of the Neva River during the 20th century     

Dmitry Lajus  Jekaterina Glazkova  Dmitry Sendek  Vadim Khaitov  Julia Lajus 《Aquatic Sciences - Research Across Boundaries》2015,77(3):411-425

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European glacial relict snails and plants: environmental context of their modern refugial occurrence in southern Siberia          下载免费PDF全文

Michal Horsák  Milan Chytrý  Petra Hájková  Michal Hájek  Jiří Danihelka  Veronika Horsáková  Nikolai Ermakov  Dmitry A. German  Martin Kočí  Pavel Lustyk  Jeffrey C. Nekola  Zdenka Preislerová  Milan Valachovič 《Boreas: An International Journal of Quaternary Research》2015,44(4):638-657

Knowledge of present‐day communities and ecosystems resembling those reconstructed from the fossil record can help improve our understanding of historical distribution patterns and species composition of past communities. Here, we use a unique data set of 570 plots explored for vascular plant and 315 for land‐snail assemblages located along a 650‐km‐long transect running across a steep climatic gradient in the Russian Altai Mountains and their foothills in southern Siberia. We analysed climatic and habitat requirements of modern populations for eight land‐snail and 16 vascular plant species that are considered characteristic of the full‐glacial environment of central Europe based on (i) fossil evidence from loess deposits (snails) or (ii) refugial patterns of their modern distributions (plants). The analysis yielded consistent predictions of the full‐glacial central European climate derived from both snail and plant populations. We found that the distribution of these 24 species was limited to the areas with mean annual temperature varying from ?6.7 to 3.4 °C (median ?2.5 °C) and with total annual precipitation varying from 137 to 593 mm (median 283 mm). In both groups there were species limited to areas with colder and drier macroclimates (e.g. snails Columella columella and Pupilla loessica, and plants Kobresia myosuroides and Krascheninnikovia ceratoides), whereas other species preferred areas with relatively warmer and/or moister macroclimates (e.g. snails Pupilla turcmenica and P. alpicola, and plants Artemisia laciniata and Carex capillaris). Analysis of climatic conditions also indicated that distributional shifts of the studied species during the Pleistocene/Holocene transition were closely related to their climatic tolerances. Our results suggest that the habitat requirements of southern Siberian populations can provide realistic insights into the reconstruction of Eurasian, especially central European, glacial environments. Data obtained from modern populations also highlight the importance of wet habitats as refugia in the generally dry full‐glacial landscape.  相似文献   

Möhnite, (NH4)K2Na(SO4)2, a new guano mineral from Pabellón de Pica,Chile     

Nikita V. Chukanov  Sergey M. Aksenov  Ramiza K. Rastsvetaeva  Igor V. Pekov  Dmitry I. Belakovskiy  Sergey N. Britvin 《Mineralogy and Petrology》2015,109(5):643-648

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Preliminary Characterisation of New Reference Materials for Microanalysis: Chinese Geological Standard Glasses CGSG‐1, CGSG‐2, CGSG‐4 and CGSG‐5     

Ming‐Yue Hu  Xing‐Tao Fan  Brigitte Stoll  Dmitry Kuzmin  Ying Liu  Yongsheng Liu  Weidong Sun  Guang Wang  Xiu‐Chun Zhan  Klaus Peter Jochum 《Geostandards and Geoanalytical Research》2011,35(2):235-251

Four silicate glasses were prepared by the fusion of about 1 kg powder each of a basalt, syenite, soil and andesite to provide reference materials of natural composition for microanalytical work. These glasses are referred to as ‘Chinese Geological Standard Glasses’ (CGSG) ‐1, ‐2, ‐4 and ‐5. Micro and bulk analyses indicated that the glasses are well homogenised with respect to major and trace elements. Some siderophile/chalcophile elements (e.g., Sn, Pt, Pb) may be heterogeneously distributed in CGSG‐5. This paper provides the first analytical data for the CGSG reference glasses using a variety of analytical techniques (wet chemistry, XRF, EPMA, ICP‐AES, ICP‐MS, LA‐ICP‐MS) performed in nine laboratories. Most data agree within uncertainty limits of the analytical techniques used. Discrepancies in the data for some siderophile/chalcophile elements exist, mainly because of possible heterogeneities of these elements in the glasses and/or analytical problems. From the analytical data, preliminary reference and information values for fifty‐five elements were calculated. The analytical uncertainties [2 relative standard error (RSE)] were estimated to be between about 1% and 20%.  相似文献   

Foreign-Area Expertise in U.S. Geography: An Assessment of Capacity based on Foreign-Area Dissertations, 1977–1991*     

B. L. Turner  Dmitry Varlyguin 《The Professional geographer》1995,47(3):308-314

Interpretations of a decline in foreign-area specialization have raised concerns about the capacity of geography in the United States to serve the expected increase in demands for foreign-area expertise. An assessment of foreign-area dissertations awarded by U.S. geography programs over a 15-year period (1977–1991) fails to support the concerns raised. No significant declines, if any at all, are found for early career interest and research in foreign areas. Several caveats are warranted, however. Geography has lost three doctoral programs with strong foreign-area dissertation records for the period in question. Also, non-U.S. citizens, many of whom do not remain in the United States after completion of their doctorate work, account for a significant proportion of foreign-area dissertations. Various questions that must be addressed to analyze the capacity question more broadly are identified.  相似文献   

Complex analysis of the damage caused by geocryologic processes (as exemplified by effects on the Chara-China Railway track, Transbaikal region)     

Irina Chesnokov  Dmitry Sergeev 《寒旱区科学》2017,9(3):335-338

The report presents an analysis of a unique data set demonstrating the influence of geocryological processes on the 75-km Chara-China Railway track (northern Transbaikal region). The originality of these investigations lies in the study of the influence of natural processes on the road in the absence of any repair works or protective and compensating measures for a long period of time (1998~2014). These conditions allowed assessment of the actual damage to the railroad.  相似文献