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461.
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本文尝试利用地层剖面岩石样品化学分析数据的聚类分析、非线性映象分析、对应分析及最优分割法等多元统计分析结果,结合地层剖面岩性特征,对遵义下—中三叠统碳酸盐岩地层沉积环境进行了初步探讨。 相似文献
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Geoid heights measured by spatial altimetry must be corrected for systematic bias due to orbital error. This requires the solution of a very large overdetermined and underconstrained system of linear equations. We present a rigorous procedure of solution by successive iterations (block relaxation method) and define its validity on a synthetic example from the Mediterranean area. 相似文献
465.
For the last sixty years, two institutions have shaped the destiny of the town of O?wi?cim in southern Poland. One of these institutions is globally recognised, its history and development widely researched; the other is well known only amongst Polish industrialists, perhaps Polish economic geographers, and amongst the people of O?wi?cim. These two institutions are the Auschwitz State Museum and the chemical firm Dwory SA. Both institutions have their roots in the German Occupation of Poland 1939-1945. This paper presents the tale of these two institutions in order not only to highlight the need to embed memorial sites in their wider contexts, but also to indicate the impact of such sites as political-economic institutions, with the influence to shape social and economic landscapes. In laying out the geographies of the town and its two major institutions, we draw attention to the ways in which Holocaust memorialisation and post-socialist transformation are articulated with each other, not only here in O?wi?cim, and also with wider processes of social, economic, political and cultural change. 相似文献
466.
Fei ZHENG Bo WU Lin WANG Jingbei PENG Yao YAO Haifeng ZONG Qing BAO Jiehua MA Shuai HU Haolan REN Tingwei CAO Renping LIN Xianghui FANG Lingjiang TAO Tianjun ZHOU Jiang ZHU 《大气科学进展》2023,40(4):541-548
The Northern Hemisphere(NH) often experiences frequent cold air outbreaks and heavy snowfalls during La Ni?a winters. In 2022, a third-year La Ni?a event has exceeded both the oceanic and atmospheric thresholds since spring and is predicted to reach its mature phase in December 2022. Under such a significant global climate signal, whether the Eurasian Continent will experience a tough cold winter should not be assumed, despite the direct influence of mid-to high-latitude,large-scale atmospheric ... 相似文献
467.
The Mustafakemalpa?a Fault (MF), located among Manyas, Ulubat and Orhaneli faults, is a right lateral strike-slip and 47 km in length. The MF begins with a pressure ridge at the west and exhibits complex jog terminations at east ends in restraining left stepovers. The western section of the fault bounds Miocene and Quaternary units and continues towards ?lyasç?lar. The central segment of the fault, starts with approximately 750-m leftward stepover, exhibits a sinusoidal geometry between Kapakl?oluk and Kabulbaba. In this section, MF traverses mountainous terrain and cuts Ophiolite, Jurassic limestones and Miocene detritals, forming dextral faulting features and gaining reverse component. The eastern section exhibits left stepping en-echelon pattern and consists 2.5-km offset on the Orhaneli River. In this study, palaeoseismological findings related to the Holocene activity and active tectonic properties of the MF are presented. The trenches exposed mismatched stratigraphy, demonstrating evidence of events across the fault. We identified three events (before BC 2190, later AD 1425 and 1850) that have occurred during the past 4000 years. We suggest a long non-characteristic recurrence interval and ~0.7 mm/y slip-rate for MF, based on trench data and offset of the Late Pliocene drainage of Orhaneli River. 相似文献
468.
P. F. Zanazzi P. Comodi S. Nazzareni N. Rotiroti S. van Smaalen 《Physics and Chemistry of Minerals》2007,34(1):23-29
The thermal evolution of 10-Å phase Mg3Si4O10(OH)2·H2O, a phyllosilicate which may have an important role in the storage/release of water in subducting slabs, was studied by X-ray single-crystal diffraction in the temperature range 116–293 K. The lattice parameters were measured at several intervals both on cooling and heating. The structural model was refined with intensity data collected at 116 K and compared to the model refined at room temperature. As expected for a layer silicate on cooling in this temperature range, the a and b lattice parameters undergo a small linear decrease, α a = 1.7(4) 10?6 K?1 and α b = 1.9(4) 10?6 K?1, where α is the linear thermal expansion coefficient. The greater variation is along the c axis and can be modeled with the second order polynomial c T = c 293(1 + 6.7(4)10?5 K?1ΔT + 9.5(2.5)10?8 K?2(ΔT)2) where ΔT = T ? 293 K; the monoclinic angle β slightly increased. The cell volume thermal expansion can be modeled with the polynomial V T = V 293 (1 + 8.0 10?5 K?1 ΔT + 1.4 10?7 K?2 (ΔT)2) where ΔT = T ? 293 is in K and V in Å3. These variations were similar to those expected for a pressure increase, indicating that T and P effects are approximately inverse. The least-squares refinement with intensity data measured at 116 K shows that the volume of the SiO4 tetrahedra does not change significantly, whereas the volume of the Mg octahedra slightly decreases. To adjust for the increased misfit between the tetrahedral and octahedral sheets, the tetrahedral rotation angle α changes from 0.58° to 1.38°, increasing the ditrigonalization of the silicate sheet. This deformation has implications on the H-bonds between the water molecule and the basal oxygen atoms. Furthermore, the highly anisotropic thermal ellipsoid of the H2O oxygen indicates positional disorder, similar to the disorder observed at room temperature. The low-temperature results support the hypothesis that the disorder is static. It can be modeled with a splitting of the interlayer oxygen site with a statistical distribution of the H2O molecules into two positions, 0.6 Å apart. The resulting shortest Obas–OW distances are 2.97 Å, with a significant shortening with respect to the value at room temperature. The low-temperature behavior of the H-bond system is consistent with that hypothesized at high pressure on the basis of the Raman spectra evolution with P. 相似文献
469.
D. R. Franco T. S. Berquó R. A. L. Imbernon C. S. M. Partiti J. Enzweiler 《Environmental Geology》2007,52(5):831-842
In the present work, we investigate the iron oxides and oxyhydroxides behavior and evolution, related to the geochemical behavior of some metals, which could be retained as solid phases in the sediments from an urban water reservoir lake, placed in Taiaçupeba, Great São Paulo, Brazil. These tasks were performed by the establishment of a proceduring setting for environmental monitoring analysis through Mössbauer spectroscopy measurements associated to hysteresis loops measurements and chemical analysis [X-ray fluorescence (XRF)]. We inferred the possibility of goethite occurrence in broad particle size distribution (5–50 nm), and related to ferrihydrite, and small grain-size hematite (about 8 nm). The magnetometry results pointed to the paramagnetic/superparamagnetic behavior of the magnetic phases present in the samples and also suggested the occurrence of small grain-size magnetite. We also verified the presence of clay minerals related to Fe, as well as the occurrence of Fe3+ and/or Fe2+ in short-range structural order. Through a straight correlation among Mössbauer spectra data gained at T = 77 K and Al-metal, metal-Fe molar ratios, provided through XRF data, we found remarkable indications of interference on meta-stable phases evolution to its final products. Such results can be pointing for evidences about the possible isomorphic replacing and/or adsorption of Al and other metals in goethite and hematite. 相似文献
470.
Record-breaking heavy and persistent precipitation occurred over the Yangtze River Valley (YRV) in June-July (JJ) 2020. An observational data analysis has indicated that the strong and persistent rainfall arose from the confluence of southerly wind anomalies to the south associated with an extremely strong anomalous anticyclone over the western North Pacific (WNPAC) and northeasterly anomalies to the north associated with a high-pressure anomaly over Northeast Asia. A further observational and modeling study has shown that the extremely strong WNPAC was caused by both La Ni?a-like SST anomaly (SSTA) forcing in the equatorial Pacific and warm SSTA forcing in the tropical Indian Ocean (IO). Different from conventional central Pacific (CP) El Ni?os that decay slowly, a CP El Ni?o in early 2020 decayed quickly and became a La Ni?a by early summer. This quick transition had a critical impact on the WNPAC. Meanwhile, an unusually large area of SST warming occurred in the tropical IO because a moderate interannual SSTA over the IO associated with the CP El Ni?o was superposed by an interdecadal/long-term trend component. Numerical sensitivity experiments have demonstrated that both the heating anomaly in the IO and the heating anomaly in the tropical Pacific contributed to the formation and maintenance of the WNPAC. The persistent high-pressure anomaly in Northeast Asia was part of a stationary Rossby wave train in the midlatitudes, driven by combined heating anomalies over India, the tropical eastern Pacific, and the tropical Atlantic. 相似文献