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991.
SHAZongyao BIANFuling 《地球空间信息科学学报》2005,8(1):57-63
This paper introduces some definitions and defines a set of calculating indexes to facilitate the research, and then presents an algorithm to complete the spatial clustering result comparison between different clustering themes. The research shows that some valuable spatial correlation patterns can be further found from the clustering result comparison with multi-themes, based on traditional spatial clustering as the first step. Those patterns can tell us what relations those themes have, and thus will help us have a deeper understanding of the studied spatial entities. An example is also given to demonstrate the principle and process of the method. 相似文献
992.
The various steps required for compilation of a bathymetric chart of the Gulf of Finland are outlined, taking into account the specific conditions characteristic of that water body. The use of available initial source materials and special survey work required for supplementing these sources is discussed. Translated by Edward Torrey, Alexandria, VA 22308 from: Geodeziya i kartografiya, 1988, No. 8, pp. 40-42. 相似文献
993.
Nazarova L. B. Razjigaeva N. G. Diekmann B. Grebennikova T. A. Ganzey L. A. Belyanina N. I. Arslanov K. A. Kaistrenko V. M. Gorbunov A. O. Kharlamov A. A. Golovatyuk L. V. Syrykh L. S. Subetto D. A. Lisitsyn A. P. 《Doklady Earth Sciences》2019,486(1):494-497
Doklady Earth Sciences - Results of a paleolimnological investigation of a well-dated lake sediment section from Shikotan Island (Southern Kurils) showed that from ca 8.0 to 5.8 cal ka BP a warm... 相似文献
994.
J. Zverko I. Iliev I. Romanyuk I. Barzova D. Kudryavtsev I. Stateva E. Semenko 《Astrophysical Bulletin》2012,67(1):57-66
Axial rotation of a star plays an important role in its evolution, physical condition in its atmosphere and appearance of its spectrum. Methods of determinations of υ sin i are based on comparison of the observed profiles of spectral lines with theoretical ones. Their accuracy depends on the kind and quality of spectrograms as well as on the algorithms used. A frequently used method is the simple comparing of one line, e.g. the Ca II at 3933 Å or Mg ii at 4481 Å. This however, may result in a false value of υ sin i if low dispersion spectra are used. In this work we studied contemporary CCD as well as older photographic spectra of the multiple star HD90569. We determined the projected rotational velocity value to be υ sin i = 11 km/s. Besides formerly reported enhancing of lines of Cr, Fe, Mn and Sr, we found also large overabundances of rare earths, gallium and platinum. Helium, carbon, nitrogen, oxygen, aluminium, calcium, scandium and nickel are in deficit. The spectrum of the occultation double was not identified to be of the SB2-type, however, there are some observable evidences that the pair creates a binary with a long orbital period. Despite this there are also observations that leave such interpretation uncertain. 相似文献
995.
Abstract The detailed characteristics of a CASPII warm frontal passage are presented in this article. This storm, Intensive Operating Period (IOP) 13 (February 26–27, 1992), was observed in detail with an array of diverse instruments. It has the advantage over earlier freezing precipitation studies of having simultaneous, in situ and remote sensing measurements by aircraft and ground‐based Doppler radar. The associated precipitation was in the form of banded structures parallel to the front. Within these bands were embedded precipitation cores, some parallel to the band, some perpendicular. The warm front itself was characterized by major perturbations in its kinematic and thermodynamic features. The cores oriented parallel to the front were the result of embedded convection generated, at least in part, by the irregularities in the frontal surface. The cores oriented perpendicular to the front were closely associated with the 0°C isotherm on the underside of the frontal inversion. Precipitation phase changes played a significant role in the occurrence of wide near 0°C regions, both vertically and horizontally. These regions had a profound influence on the observed precipitation types and led to complex precipitation‐thermodynamic‐dynamic interactions. Instabilities produced by these interactions are seen in wave‐like features observed by the Doppler radar in these regions, both parallel and perpendicular to the frontal zone. 相似文献
996.
Geochemistry and Intrusive History of the Ashland Pluton, Klamath Mountains, California and Oregon 总被引:2,自引:1,他引:2
GRIBBLE ROBERT F.; BARNES CALVIN G.; DONATO MARY M.; HOOVER JAMES D.; KISTLER RONALD W. 《Journal of Petrology》1990,31(4):883-923
The Ashland pluton is a calc-alkaline plutonic complex thatintruded the western Paleozoic and Triassic belt of the KlamathMountains in late Middle Jurassic time. The pluton comprisesa series of compositionally distinct magma pulses. The oldestrocks are hornblende gabbro and two-pyroxene quartz gabbro withinitial 87Sr/86Sr = 0{dot}7044, 18O = 8{dot}7%, and REE patternswith chondrite normalized La/Lu = 7. These units were followedby a suite of tonalitic rocks (LaN/LuN = 7) and then by a suiteof K2O- and P2O5 rocks of quartz monzodioritic affinity (LaN/LuN= 1321; LaN/SmN = 2{dot}43{dot}) The quartz monzodioriticrocks were then intruded by biotite granodiorite and granitewith lower REE abundances but more fractionated LREE(LaN/LuN= 1319; LaN/SmN = 4{dot}36 and they, in turn,were host to dikes and bosses of hornblende diorite. The latestintrusive activity consisted of aplitic and granitic dikes.Combined phase equilibria and mineral composition data, indicateemplacement conditions of approximately Ptotal = 2{dot}3kb,PH2O between 1{dot}5 and 2{dot}2 kb, and fO2 between the nickel-nickeloxide and hematite-magnetite buffers. Successive pulses of magma display increasing SiO2 togetherwith increasing 18O and decreasing initial 87Sr/86Sr. The isotopicdata are consistent with either (1) combined fractional crystallizationof andesitic magma and concurrent assimilation of crustal materialcharacterized by low Sr1 and high (18O or, more probably, (2)a series of partial melting events in which sources were successivelyless radiogenic but richer in 18O Each intrusive stage displaysevidence for some degree of crystal accumulation and/or fractionalcrystallization but neither process adequately accounts fortheir compositional differences. Consequently, each stage appearsto represent a distinct partial melting or assimilation event. The P2O5-rich nature of the quartz monzodiorite suite suggestsaccumulation of apatite. However, the suite contains abundantmafic microgranitoid enclaves and most apatite in the suiteis acicular. These observations suggest that magma mixing affectedthe compositional variation of the quartz monzodiorite suite.Mass balance calculations are consistent with a simple mixingprocess in which P2O5-rich alkalic basalt magma (representedby the mafic microgranitoid enclaves) was combined with a crystal-poorfelsic magma (represented by the tonalite suite), yielding aquartz monzodioritic magma that then underwent differentiationby crystal fractionation and accumulation. 相似文献
997.
998.
D. A. Henry 《Australian Journal of Earth Sciences》2013,60(2):251-260
The rare calc‐silicate minerals cuspidine, bultfonteinite, foshagite and xonotlite occur in a calcsilicate skarn zone near Chesney Vale, in northern Victoria. They are associated with andradite-grossular garnet, vesuvianite, diopside, wollastonite, prehnite, epidote, fluorite, calcite, perovskite,sphene and possibly tobermorite. The calc‐silicate skarn zone has formed in thermally meta‐morphosed, Ordovician, deep‐marine sediments adjacent to an Early Devonian aplitic granite pluton. The assemblages are estimated to have formed at low pressure (<100 MPa) at temperaturesnot exceeding 600°C in the presence of a low‐Xco2 fluorine‐bearing fluid. The occurrence is the firstrecord of bultfonteinite and foshagite in Australia and the first record of cuspidine and xonotlite inVictoria. 相似文献
999.
Sediment shear Q from airgun OBS data 总被引:2,自引:0,他引:2
P. D. Bromirski L. N. Frazer F. K. Duennebier 《Geophysical Journal International》1992,110(3):465-485
1000.
Nitin D. Rai Tor A. Benjaminsen Siddhartha Krishnan C. Madegowda 《Singapore journal of tropical geography》2019,40(1):124-139
Protected areas have had significant impacts on local communities primarily through the physical removal of people. In some instances, people continue to live within protected areas due to the inability of the state to evict them. The restrictions on livelihoods placed on people living inside protected areas lead to in situ displacement. We show how conservation enclosures in the Biligiri Rangaswamy Temple Tiger Reserve have produced a class of people that the state ‘lets die’ by banning customary practices such as fire use, hunting and harvesting of forest produce. Using longitudinal ethnographic, socio‐economic and ecological data, we demonstrate that conservation policy has alienated indigenous forest dwellers from their agricultural and forest‐land. The outcomes of conservation policy include dispossession through increased crop losses, reduced income from agriculture and forest produce, as well as a forest that is dominated by weeds due to fire suppression. The ban on hunting in particular has increased wildlife densities, which has enabled the state to accumulate revenues through the establishment of wildlife tourism facilities. All in all, centralized protected area governance has changed the relationships among people, forest and the state in a way that has produced adverse effects for both livelihoods and the ecosystem. 相似文献