Extension of the solution of Kepler's equation to high eccentricities     

Sandro Da Silva Fernandes 《Celestial Mechanics and Dynamical Astronomy》1994,58(3):297-308

The classic Lagrange's expansion of the solutionE(e, M) of Kepler's equation in powers of eccentricity is extended to highly eccentric orbits, 0.6627 ... <e<1. The solutionE(e, M) is developed in powers of (e–e*), wheree* is a fixed value of the eccentricity. The coefficients of the expansion are given in terms of the derivatives of the Bessel functionsJ _n (ne). The expansion is convergent for values of the eccentricity such that |e–e*|<(e*), where the radius of convergence (e*) is a positive real number, which is calculated numerically.  相似文献   

科技管理兼盈——纪念程裕淇院士诞辰110周年     

耿元生 《地质学报》2022,96(9):2955-2966

程裕淇院士是我国著名的变质岩石学家、矿床学家和前寒武纪地质学家。中国科学院学部委员(院士)，中国人民政治协商会议第四届、第五届全国委员会委员，第六届、第七届全国政协常务委员会委员。程裕淇先生开拓了我国变质岩研究领域，提出了矿床成矿系列理论，发展了我国前寒武纪地质学。他在管理上积极推进地质行业的对外开放，促进国际合作交流，为建立中央直属的野战军队伍建言献策；在政协多次提案，推动了我国矿产资源法的立法和实施。  相似文献   

System for normalization of a hamiltonian function based on lie series     

Krzysztof Gozdziewski  Andrzej J. Maciejewski 《Celestial Mechanics and Dynamical Astronomy》1990,49(1):1-10

A software system for normalization of a Hamiltonian function is described. A few examples of its applications are given. It is written in PASCAL and runs on an IBM XT/AT with 640 KB memory.  相似文献   

Multiple magnetization events in the Red River carbonates, Williston Basin, Canada: Evidence for fluid-flow?     

Erika Szabo  Maria T. Cioppa   《Journal of Geochemical Exploration》2006,89(1-3):384

Samples collected from the Upper Ordovician Red River carbonates in a well at the centre of the Williston Basin revealed two paleomagnetic components with different inclinations, 60.3 ± 3.9° (k = 70.7, N = 12) and 20.4 ± 3.3° (k = 141.2, N = 8), but similar declination values in individual specimens. Inclination-only analysis indicates two possible scenarios for the age of these two magnetizations: in scenario (a) the timing of magnetization happened sometime between Late Ordovician to Devonian; and in scenario (b) there are two different remagnetizations, one that overlaps Pennsylvanian to Permian time while the other can have either a Late Jurassic or a Tertiary age. Whereas dolomitization and some isotopic data tend to support scenario (a), previous paleomagnetic data from the Williston Basin and from younger units in the same well, the tectonic evolution of the basin, and the hydrocarbon maturation pattern in the Red River carbonates all favour chemical remagnetization(s) driven by orogenic fluids during the Alleghenian and Laramide orogenies.  相似文献   

New specimens of a fossil ostrich from the Miocene of Kenya   总被引：1，自引：0，他引：1  

Leona M. Leonard  Gareth J. Dyke  Cyril A. Walker 《Journal of African Earth Sciences》2006,45(4-5):391-394

Fossilised hind limb bones from the late Middle Miocene (approximately 14 million-year-old [MYA]) Fort Ternan, Kadianga West and Ngorora localities in Western Kenya indicate the presence of a new representative of the ostrich genus Struthio. These new fossils represent some of the oldest known records for Struthio yet described, slightly younger than Struthio coppensi, from the Lower Miocene of Namibia. Because the four sub-species of the modern-day ostrich (Struthio camelus camelus, Struthio camelus australis, Struthio camelus massaicus, and Struthio camelus molybdophanes) inhabit the plains of Africa, and as recently as the 1940s, a fifth sub-species was also present in the Middle East and Saudi Arabia (Struthio camelus syriacus), records of Struthio from Kenya and Namibia testify to the much wider distribution of these cursorial birds in the relatively recent past. This is further supported by the very high frequency of ostrich eggshell fragments found across Africa and Eurasia, which vastly outweighs the amount of skeletal material uncovered over the last century.  相似文献   

A pronounced dry event recorded around 4.2 ka in brine sediments from the northern Red Sea     

Helge W. Arz  Frank Lamy  Jürgen Ptzold 《Quaternary Research》2006,66(3):432-441

Partly laminated sediments were sampled from the brine-filled, anoxic Shaban Deep basin in the northern Red Sea. At about 4200 cal yr BP more than two millennia of anoxic sedimentation is replaced by a sub-oxic facies strongly suggesting the episodic absence of the brine. At the same time stable oxygen isotopes from surface dwelling foraminifera show a sharp increase (within less than 100 yr) pointing to a strong positive salinity anomaly at the sea surface. This major evaporation event significantly enhanced the renewal of deep water and the subsequent ventilation of the small Shaban Deep basin. The timing and strength of the reconstructed environmental changes around 4200 cal yr BP suggest that this event is the regional expression of a major drought event, which is widely observed in the neighboring regions, and which strongly affected Middle East agricultural civilizations.  相似文献   

Présence d'une mangrove à Avicennia au Miocène moyen dans la région de Digne (Alpes-de-Haute-Provence,France) : implications stratigraphiques et paléoclimatiques     

Jean-Jacques Châteauneuf  Hugues Bauer  Isabelle Cojan 《Comptes Rendus Geoscience》2006,338(3):197-205

Avicennia pollen grains have been discovered in marine facies from the Middle Miocene deltaic series of Châteauredon (southeastern France). Based on the local stratigraphy, an age between 15.8 and 16.5 Ma is proposed for these grains. The age and the transgressive context of the Avicennia bearing-levels are in agreement with the maximum extension of the mangrove known in the western Mediterranean during interval N8–NN4 pro parte, in relation with the Langhian highstand. This mangrove occurrence at 42°N latitude during Middle Miocene is a more northern witness of the mangrove sites known in Languedoc and Provence areas. It also implies a lower climatic gradient than today. To cite this article: J.-J. Châteauneuf et al., C. R. Geoscience 338 (2006).  相似文献   

Alpine reworking of Ordovician protoliths in the Western Carpathians: Geochronological and geochemical data on the Muráñ Gneiss Complex, Slovakia     

A.S. Gaab  M. Jank  U. Poller  W. Todt 《Lithos》2006,87(3-4):261-275

Magmatic protoliths of Ordovician age have been identified in the metamorphic rocks of the Muráñ Gneiss Complex, Veporic Unit (Central Western Carpathians). Vapor digestion single zircon U–Pb dating yields an intrusion age of 464 ± 35 Ma (upper intercept) for the granite protolith. A lower intercept age of 88 ± 40 Ma records amphibolite-facies metamorphic overprint in the Cretaceous, during the Alpine orogeny. Geochemical and isotopic data suggest crustal origin of the orthogneiss. Nd_initial are between − 2.6 and − 5.0 and T_DM^Nd between 1.3 and 1.5 Ga (two-step approach). ⁸⁷Sr / ⁸⁶Sr_initial ratios vary between 0.7247 and 0.7120, and a steep REE pattern further constrains the crustal affinity of these rocks. Associated amphibolite bodies have Nd_initial values of 6.5, ⁸⁷Sr / ⁸⁶Sr_initial ratio of 0.7017, and a flat REE pattern. They are interpreted as MORB derived metabasites. Whole-rock Pb isotope analyses define a linear array in a ²⁰⁶Pb / ²⁰⁴Pb vs. ²⁰⁷Pb / ²⁰⁴Pb diagram with an age of ca. 134 Ma, consistent with intense Alpine metamorphism and deformation.

These basement rocks of the Central Western Carpathians are interpreted as Ordovician magmatic rocks intruded at an active margin of Gondwana. They represent the eastern prolongation of Cambro–Ordovician units of the European Variscides, which were part of the peri-Gondwana superterrane and accreted to Laurussia during the Variscan orogeny. Variscan metamorphic overprint is not recorded by the isotopic data of the Muráñ Gneiss Complex. Alpine metamorphism is the most dominant overprint.  相似文献   

Real eukaryotes and precipitates first found in the Middle Riphean stratotype, southern Urals   总被引：1，自引：0，他引：1  

V. N. Sergeev  Lee Seong-Joo 《Stratigraphy and Geological Correlation》2006,14(1):1-18

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Reliability Based Assessment of Shallow Foundations Using Mathcad     

Ahmad Shlash Alawneh  Osama K. Nusier  Ahmed Abdul-Ezel Al-Mufty 《Geotechnical and Geological Engineering》2006,24(3):637-660

A reliability based method was used to design and analyse shallow foundations using first-order Taylor series approximation. The computer program Mathcad was used to facilitate all mathematical and computional efforts. This method is an effective tool to assist the foundation designers and analyists to investigate how reliable their designs or analyses are in relation to the ultimate bearing capacity of the foundations. The approach presented in this paper provides a reliable alternative for design and analysis of shallow foundations, rather than the conventional design methods, which employs the assumptions of a specified saftey factor. Several examples were presented for design and analysis of strip footings embedded in sandy soil, and rectangular and square footings analysis embedded in clayey soils. The program input and output of each example are also presented and discussed.  相似文献