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21.
In this paper periodic solutions of the third sort for restricted problem of three bodies in the three-dimensional space are derived numerically by starting from generating solutions obtained by one of the authors (1969) and by increasing the mass-ratio of the two primaries stepwise from zero to about 1000 for 21, 32 and 61 cases of commensurable mean motions. Periodic solutions both for circular and elliptic orbits of the primaries are obtained.The stability of the periodic solutions for the 21 circular case is discussed and it is found that none of them is linearly stable. 相似文献
22.
Yoshihide Ohta Alexander N. Larionov Alexander M. Tebenkov Claude Lepvrier Henri Maluski Michael Lange Barbara Hellebrandt 《Polar research》2002,21(1):73-89
North-west Spitsbergen consists of a complex of Caledonian and Grenvillian crystalline rocks, situated at the north-west corner of the Barents Shelf. The aim of this study is to understand the extent of pre-Caledonian basement rocks and their protoliths. Micas and zircon grains from six rocks from north-west Spitsbergen have been dated by the 40 Ar/39 Ar and single-zircon Pb-evaporation methods. Two grey granites yielded Late Caledonian mica 40 Ar/39 Ar and zircon ages of ca. 420-430 My, with inherited zircon grains as old as 1725 My. Zircon grains from a gneissose granite xenolith in a grey granites gave crystallization ages of ca. 960 My; some grains from a migmatite neosome show similar ages. Zircon grains yielding Archean and late Palaeoproterozoic ages (1600-1800 My) are interpreted as xenocrysts of detrital origin. The youngest ages obtained from detrital zircon grains from a greenschist facies quartzite of the Signehamna unit are ca. 1800 My. Similar schists are included as xenoliths in the 960 My old gneissose granite; therefore, the sedimentary protoliths of the unit are Mesoproterozoic. The dating results suggest a significant tectonothermal event during Grenvillian time; subsequent Caledonian events had less extensive thermal effects. However, it is still a matter of debate whether Grenvillian or Caledonian metamorphism produced the majority of the migmatites. A large population of zircon grains with Late Palaeoproterozoic ages suggests a wide surface exposure of rocks of this age in the source area, with some Archean zircons. 相似文献
23.
Keisuke Ishida Yasuyuki Tsujino Takeshi Kozai Tadashi Sato Francis Hirsch 《中国科学D辑(英文版)》2009,52(12):1910-1923
The last appearance datum of the radiolarian Kilinora spiralis is recorded above the first appearance datum of the ammonite Ataxioceras (A.) kurisakense in the Todoro Section of the Kurisaka Formation, Southern Kurosegawa Terrane, Shikoku, SW Japan. The constraint by ammonite
age prolongs the range of the Kilinora spiralis Zone, a remarkable Jurassic radiolarian zone in Japan-NW Pacific region, into the lower Kimmeridgian. The direct correlation
of the Kilinora spiralis zone with the Late Jurassic ammonite faunal succession in the Kurisaka Formation will provide a clue to the still pending
chronological difference between European and North American radiolarian zones. 相似文献
24.
Yoshihide Wada Benjamin F. Chao Jida Wang Min-Hui Lo Chunqiao Song Yuwen Li Alex S. Gardner 《Surveys in Geophysics》2017,38(1):131-152
Sea level rise is generally attributed to increased ocean heat content and increased rates glacier and ice melt. However, human transformations of Earth’s surface have impacted water exchange between land, atmosphere, and ocean, ultimately affecting global sea level variations. Impoundment of water in reservoirs and artificial lakes has reduced the outflow of water to the sea, while river runoff has increased due to groundwater mining, wetland and endorheic lake storage losses, and deforestation. In addition, climate-driven changes in land water stores can have a large impact on global sea level variations over decadal timescales. Here, we review each component of negative and positive land water contribution separately in order to highlight and understand recent changes in land water contribution to sea level variations. 相似文献
25.
Y. Kozai 《Journal of Geodesy》1968,42(3):355-357
From periodic variations of the orbital inclinations of three artificial satellites 1959Alpha 1, 1960Iota 2, and 1962Beta Mu 1 Love’s number of the earth and time lag of the bodily tide due to the friction are determined, respectively,0.29±0.03 and(10±5) minutes in time.
While the previous paper on the determination of Love’s number of the earth (Kozai, 1967) was in press, a minor error was
discovered in the Differential Orbit Improvement program(DOI) of the Smithsonian Astrophysical Observatory(SAO). Since the analysis was based on time-variations of the orbital inclinations which were derived by theDOI from precisely reduced Baker-Nunn observations, it is likely that the results in the previous paper was affected by the error
in theDOI. Therefore, the analysis is iterated by using the revisedDOI. Three satellites, 1959Alpha 1 (Vanguard 2), 1960Iota 2 (rocket ofEcho 1), and 1962Beta Mu 1 (Anna) (see Table 1) are adopted for determining Love’s number in the present paper. The satellite, 1959Eta, which was used in the previous paper, is not adopted here, since the inclination of this satellite shows irregular variations
unexplained. Instead of 1959Eta 1962Beta Mu 1 is adopted as orbital elements from precisely reduced Baker-Nunn observations have become available for a long interval of
time for this satellite. 相似文献
26.
Seasonal variations in coastal debris on Awaji Island, Japan 总被引：1，自引：1，他引：0
Shimizu T Nakai J Nakajima K Kozai N Takahashi G Matsumoto M Kikui J 《Marine pollution bulletin》2008,57(1-5):182-186
The subject of our study was Awaji Island, an island located in the west of Japan that is surrounded by sea and that has serious problems relating to coastal debris. We conducted a long-term investigation focusing on three beaches and evaluated the results. The study was designed to develop an understanding of the actual situation, to inform local citizens, and raise their concerns about the problem of debris with a view to taking action against it. We obtained the following results: the amount, type, and ratio of debris changed according to weather and ocean conditions; debris also differs according to geographical conditions; social and economic activities of the surrounding area influence the type of debris encountered. Following this study, we have continued our investigation, and are continuing to gather data. At the same time, it is important to spread our ideas and enlighten people so as to encourage them not to dump debris. We hope that these actions manage to raise the level of consciousness among local citizens and to expand their anti-debris activities. 相似文献
27.
Don P. Chambers Anny Cazenave Nicolas Champollion Habib Dieng William Llovel Rene Forsberg Karina von Schuckmann Yoshihide Wada 《Surveys in Geophysics》2017,38(1):309-327
Evaluating global mean sea level (GMSL) in terms of its components—mass and steric—is useful for both quantifying the accuracy of the measurements and understanding the processes that contribute to GMSL rise. In this paper, we review the GMSL budget over two periods—1993 to 2014 and 2005 to 2014—using multiple data sets of both total GMSL and the components (mass and steric). In addition to comparing linear trends, we also compare the level of agreement of the time series. For the longer period (1993–2014), we find closure in terms of the long-term trend but not for year-to-year variations, consistent with other studies. This is due to the lack of sufficient estimates of the amount of natural water mass cycling between the oceans and hydrosphere. For the more recent period (2005–2014), we find closure in both the long-term trend and for month-to-month variations. This is also consistent with previous studies. 相似文献
28.
Takeshi Kozai Lydia Perelis-Grossowicz Annachiara Bartolini Chotima Yamee José Sandoval Francis Hirsch Keisuke Ishida Thasinee Charoentitirat Assanee Meesook Jean Guex 《Gondwana Research》2011,19(1):37-46
The paleontological investigations of the Jurassic of Western Thailand, districts of Mae Sot (Tak–Mae Sot highway, Padaeng Tak and Ban Mae Kut Luang Zinc mines) and Umphang (Klo Tho), provide age constraints for the Late Indosinian orogeny, the Paleotethys closure and the timing of the marine Jurassic inundation of Sundaland. The basal conglomerate of the Jurassic is derived from the pelagic Triassic Mae Sariang substratum. Stratigraphy, microfacies and paleontology of the Jurassic marine strata focus especially on ammonites, bivalves, large benthic foraminifera and algae. Among ammonites, the Tethyan Catulloceras perisphinctoides Gemmellaro marks the Upper Toarcian (Aalensis Zone) along the Tak–Mae Sot highway and Riccardiceras longalvum (Vacek), Malladaites pertinax (Vacek), Abbasites sp. and Vacekia sp. indicate Middle Aalenian to lowermost Bajocian in the Padaeng Mine (SE of Mae Sot) and Klo–Tho (Umphang). Vacekia sp., Spinammatoceras schindewolfi Linares and Sandoval and Malladaites vaceki Linares and Sandoval indicate Middle Aalenian to lowermost Upper Aalenian at Ban Mae Kut Luang (NE of Mae Sot). Among foraminifers, the large benthic foraminifer Timidonella sarda Bassoullet, Chabrier and Fourcade in the Western Tethys is indicative for Aalenian–Bajocian times, as characterized in the section at the Tak–Padaeng Zinc mine and the Klo–Tho Formation near Umphang. The endemic foraminifer Gutnicella kaempferi characterizes the Pu Khloe Khi Formation near Umphang. Among bivalves, shallow marine, dominantly endemic fauna includes Parvamussium donaiense (Mansuy) and Bositra ornate (Quenstedt), from the Toarcian to the Early Bajocian. A consideration of the faunal affinity shows that the fauna is partly endemic with Northern Tethyan (Eurasian) affinity. 相似文献
29.
Clinopyroxene phenocrysts in the Kokchetav trachybasalts are variable in composition and textures. Two distinctive cores are recognized: diopside cores and green salite cores. The diopside cores with Mg# of 80–90 are mantled by colorless salite rims with Mg# of 70–80. The green salite cores have especially low Mg# (<70) but high Al and Ti contents. A Mg-rich band (Mg#=82–90) usually occurs between a green salite core and its rim, and/or between a colorless salite mantle and its rim. Dissolution surfaces are observed on all textural variants. Two magma chambers are needed to explain the observed clinopyroxene phenocrysts. A deep chamber at about 120 km in the upper mantle in which diopside cores crystallized, and a shallow chamber at depths of less than 40 km in which diopside cores were resorbed and overgrown by salite rims or mantles. Magma mixing in the shallow chamber is responsible for the formation of dissolution surfaces between the diopside bands and the colorless salite mantles. The dissolution surfaces on the diopside cores formed in the shallow chamber as a result of pressure decrease. This magma evolution scenario is complicated by the occurrence of the crustal-origin green salite cores in diopsides. These green cores likely represent the relics of continental materials, which were captured in the deep chamber and partially re-melted. Our observations indicate that subducted continental materials were returned to the Earth's surface as a result of magmatism. This study therefore provides direct evidence of a link between subducted continental materials (slab) and magmatism in this orogenic belt. 相似文献
30.
Formed during an early compressional period in the opening of North Atlantic Ocean, a Tertiary fold-thrust belt extends along the mid-to- southern part of the western coast of Spitsbergen. Complex thrust structures involve the basement (Caledonian and older) and many shallow dipping thrust faults dissect the overlying cover rocks (Devonian and younger) in Oscar II Land in the northern part of the belt. Some of these faults occur within the basement rocks with slivers or fault blocks of the cover rocks from south-western Brøggerhalvøya to innermost St. Jonsfjorden in north-eastern Oscar II Land. Six of the slivers contain Carboniferous rocks and one is a fault-bounded block with Devonian rocks. These steeply west-dipping faults form a complex fault system- EOFC (Engelskbukta-Osbornbreen Fault Complex) - within the basement area. The lithological units of the basement are separated by faults within the EOFC, which is structurally continuous with the Brøggerhalvøya fold-thrust zone to the north and is thought to continue to the fold-thrust zone on the south-eastern coast of St. Jonsfjorden. Some previous authors considered that the two lithologically contrasting Vendian diamictites and intervening Moefjellet Formation are stratigraphically continuous and defined two separate tilloid successions in the present area. This interpretation has been extended over the whole of western Spitsbergen. However, the present study indicates that these two tilloid formations and the Moefjellet Formation are separated by the faults, probably thrusts, within the EOFC and are not in a continuous stratigraphic relation. Therefore, the two-stage history of Vendian glaciation seems questionable. 相似文献