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131.
针对目前滑坡分类复杂且侧重于理论研究的现状,通过以滑面深度、滑床岩性、滑面倾角三要素为分类重点,首次从治理角度上对滑坡进行新的分类,共划分出12种滑坡类型;对当前各种处治方法的应用范围、优缺点进行了详细的论述,从而针对不同类型的滑坡,建立了滑坡的处治模式,最后指出了滑坡处治中应注意的问题。  相似文献   
132.
The equations of state for degenerate electron and neutron gases are studied in the presence of magnetic fields. After including quantum effects in the investigation of the structural properties of these systems, it is found that some hypermagnetized stars can be unstable according to the criterion of stability of pressures. Highly magnetized white dwarfs should collapse producing a supernova type Ia, while superstrong magnetized neutron stars cannot stand their own magnetic field and must implode, too. A comparison of our results with a set of the available observational data of some compact stars is also presented, and the agreement between this theory and observations is verified.  相似文献   
133.
The Domingos Petrolini Swamp, located on the Southern Coastal Plain of Rio Grande do Sul, near the town of Rio Grande, constitutes an ample holocene lagoonal deposit. Events related to the holocene transgression and their diverse phases of glacial-eustatic ocillations were found through palynological analysis. Bases on these palynological data, four distinct phases to the paleoenvironmental evolution of the ecosystem were identified. It has also shown a transgressive restricted marine sequence on the base , which suggests the existence of a coastal brackish lagoon or a marisme type of environment. Later, there was a gradation for continentality conditions along with a scarce pollinical record. The third phase is characterized by the presence of marine components and halophyte vegetation, showing another transgressive event in that place. Lastly, the end of direct marine influence over the swamp was recorded and also the vegetation development as it appears these days.  相似文献   
134.
地震大形势研究结果表明,我国大陆地区(含边境)1999年已进入为期12年的相对平静幕,幕内可能发生3次7级地震,最大震级不超过7.2级。首发7级地震为2000年6月8日缅甸7级(位于中缅边境)。预计第二个7级地震危险时间在2005±0.5年。第三个在2008年前后。分析了我国主要地震区强震概率增益,给出了3个危险地点。未来3年即2001~2003年是相对安全时段,我国大陆不会发生7级以上破坏性地震。2011~2020年可能进入新世纪第一个7级大地震相对活跃幕,预计该幕持续10年, 可发生10次7~7.6级大震。  相似文献   
135.
工程场地条件评定中的地脉动研究   总被引:13,自引:2,他引:13  
为了研究开发更经济,更简便的场地动务特性探测方法,本文简要地回顾了工程场地条件评定中地脉动研究的演进,概述了地脉动观测技术的发展,循着地脉动分析方法的演进历程,叙述了谱和谱比分析方法,利用地脉动频散曲线反演场地速度构造的研究,讨论了各种分析方法的依据和适用条件,指出了目前存在的问题,并探讨了可能的改进途径。  相似文献   
136.
合肥盆地周缘中石炭系-二叠系碎屑岩的成分成熟度和结构2成熟度较高,成岩后生作用强烈,特别是强的机械压实作用和成岩自生矿物的多期胶结作用,使其孔隙结构和储集物性变差。盆地南缘石炭系碎屑岩成岩强度更强,孔隙结构更差。碎屑岩的孔隙类型多样,以构造裂隙和次生孔隙为主,且裂隙和次生孔隙的形成呈多期性,先期形成的次生孔隙不同程度地被后期的自生矿物充填。  相似文献   
137.
Lacustrine basins of Neogene age in Serbia were formed either in intramountain valleys-graben and half-graben structures or in the marginal part of the Pannonian sea during Oligocene or at the beginning of Miocene, lasted and ended at the end of Miocene or Pliocene. The formation of the numerous depressions of the Balkan Peninsula, due to tectonic activity, gave lake basins with alluvial, swamp and lacustrine facies. The cycle with these facies was repeated several times. The lakes are mostly meromictic, often permanently stratified (oil-shale). A high rate of sedimentation with thickness up to 2000 m is characteristic for many of these basins. In many lakes phytogenic sedimentation occurs, giving facies with coal and with oil-shales. In this paper only some basins with oil-shales will be discussed, e.g. Valjevo-Mionica, Jadar and Pranjani basin. The characteristics of Vranje and Aleksinac basin will be discussed only in general. The organic rich sequences (oil shales) are characterized by the thin lamination, preservations of fish remains and plant leaves and absence of bioturbation, which needed permanent stratification of water body and anoxic conditions. Paleoclimatic regimes at the time of deposition and diagenesis were warm, subtropic with the changes of humid and dry periods.  相似文献   
138.
A dravite from Yemen of near end-member composition was treated in air and hydrogen atmospheres at 600–900 °C to reveal changes in Mg and Al order over the octahedrally coordinated Y and Z sites, and to explore related changes in the characteristic vibrational bands in the principal (OH)-stretching frequency. Relevant information was obtained using electron microprobe analysis (EMPA), structural refinement (SREF) and polarized infrared (IR) single-crystal spectroscopy. Overall, the EMPA, SREF and IR data show that only minor changes occur during thermal treatment up to at least 800 °C, including variations in structural parameters, Mg–Al order–disorder and (OH)-stretching bands, indicating limited hydrogen loss. Untreated and treated dravite samples have very similar long-range and short-range atomic structures, which may be related to the occurrence of stable Al–Mg extended clusters around the O1 (=W) and O3 (=V) sites: W(F)–Y(MgMgMg)–V(OH)3Z[AlAlAlAlAl(Al,Mg)]; W(OH)–Y(MgMgAl)–V(OH)3Z[AlAlAlAlAl(Al,Mg)]; W(O2–)–Y(AlAlAl)–V(OH)3Z[AlAlAlAlAl(Al,Mg)]. These extended clusters remain stable to temperatures close to the observed start of decomposition (~900 °C).  相似文献   
139.
Clay mineralogy and trace-element geochemistry of two abyssal cores indicate that the primary source of surface-current-transported detrital material in the southern Grenada Basin changed from a continental, South American terrane to a volcanic, Lesser Antillean terrane at the end of the Pleistocene. The record of benthic foraminiferal assemblages demonstrates that the Caribbean Bottom Water (CBW) was relatively oxygen poor and less corrosive in late Pleistocene glacial times than in interglacial times. The change in the properties of CBW in the Holocene was related to a renewed influx of North Atlantic Deep Water in the Caribbean.  相似文献   
140.
One-point correlation analysis on upper-level meridional wind identified the existence of a teleconnection pattern in July, which emerges from North Africa to East Asia along the westerly jet in the middle latitudes. We examined the spatial and temporal structures of this teleconnection pattern, and found the unique characteristics rather different from the patterns in other elements such as geopotential height, streamfunction and vorticity. We also investigated the relationship between this teleconnection and precipitation, and suggested that the teleconnection is a possible linkage of the EASM to the Indian monsoon, and even to subtropical heating anomalies over Atlantic.  相似文献   
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