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Li+,Na+,K+/Cl-,SO2-4-H2O五元体系相图对于硫酸钠亚型富锂卤水分离提取锂盐、锂辉石加工利用和锂盐产品的开发利用工艺制定都有指导作用。20世纪50年代曾有人研究过这一体系25 ℃时的相图,限于当时的科研水平,液相组成确定不准确,对平衡固相的判断,后来诸多研究结果证明也有错误。50多年来再没有人研究这一五元体系相图。利用我们提出的Li+,Na+,K+/Cl-,SO2-4-H2O六元体系热力学模型,对该五元体系的平衡溶液组成和正确的平衡固相进行理论预测,给出了该体系的完整相图。结合硫酸锂混盐分离、加工实例阐述了该五元体系相图的应用。 相似文献
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Yih-Min Wu Hiroo Kanamori Richard M. Allen Egill Hauksson 《Geophysical Journal International》2007,170(2):711-717
We explore a practical approach to earthquake early warning in southern California by determining a ground-motion period parameter τ c and a high-pass filtered displacement amplitude parameter Pd from the initial 3 s of the P waveforms recorded at the Southern California Seismic Network stations for earthquakes with M > 4.0. At a given site, we estimate the magnitude of an event from τ c and the peak ground-motion velocity ( PGV ) from Pd . The incoming three-component signals are recursively converted to ground acceleration, velocity and displacement. The displacements are recursively filtered with a one-way Butterworth high-pass filter with a cut-off frequency of 0.075 Hz, and a P -wave trigger is constantly monitored. When a trigger occurs, τ c and Pd are computed. We found the relationship between τ c and magnitude ( M ) for southern California, and between Pd and PGV for both southern California and Taiwan. These two relationships can be used to detect the occurrence of a major earthquake and provide onsite warning in the area around the station where onset of strong ground motion is expected within seconds after the arrival of the P wave. When the station density is high, the methods can be applied to multistation data to increase the robustness of onsite early warning and to add the regional warning approach. In an ideal situation, such warnings would be available within 10 s of the origin time of a large earthquake whose subsequent ground motion may last for tens of seconds. 相似文献
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Demel Teketay 《Journal of Arid Environments》1998,38(4):551-560
Seeds ofAcacia origena,A. pilispinaandPterolobium stellatumhave a hard seed coat that hampers imbibition of water and prevents maximum, uniform and rapid germination. Therefore, the seeds were subjected to different treatments involving mechanical scarification, concentrated sulphuric acid and boiling water to break the dormancy imposed by the hard seed coat. To determine the effects of different constant temperature regimes on germination, scarified seeds were incubated on a thermogradient at 10, 15, 20, 25 and 30°C. Germination of scarified seeds was also tested in light and dark. Mechanical scarification resulted in 100% germination for theAcaciaspecies and 94% forP. stellatum. ForA. origena, sulphuric acid treatments for 60, 90 and 120 min resulted in significantly higher per cent germination (>95%) than all the other treatments. ForA. pilispina, sulphuric acid treatments for 45 and 60 min, as well as immersing seeds for 1 min in hot water, gave significantly higher per cent germination (97%) than all the other treatments. ForP. stellatum, mechanical scarification and all the acid treatments applied resulted in significantly higher per cent germination (>85%) than the control and all hot water treatments. All seeds ofP. stellatumimmersed in hot water, even for 1 min, rotted soon after sowing, indicating that they are sensitive to high temperatures. Scarified seeds of the twoAcaciaspecies germinated to a higher degree (≥90%) between 10 and 30°C, while germination of scarified seeds ofP. stellatumranged from 48 to 82% between 10 and 30°C. Scarified seeds of the three species germinated to a large extent (>70%) both in light and dark, indicating that seeds do not require light for germination. 相似文献
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David J. A. Evans 《Geografiska Annaler: Series A, Physical Geography》2000,82(4):499-512
A stratigraphic sequence exposed by river erosion in the foreland of Skalafellsjokull, southern Iceland, displays five lithofacies documenting glaciofluvial deposition followed by glaciotectonic disturbance and subglacial deformation. Lithofacies 1a and 1b are glaciotectonically thrust glaciofluvial outwash and subglacial deformation till respectively from an early advance of Skalafellsjokull. Lithofacies 2, massive gravels and clast–supported diamictons, documents the deposition of glaciofluvial outwash in the proto–River Skala prior to overriding by Skalafellsjokull during the Little Ice Age. During overriding, lithofacies 2 was glaciotectonically disturbed and now possesses the clast fabric and structural characteristics of G B (non–penetratively deformed) and G A (penetratively deformed) type glaciotectonites. A shear zone separates lithofacies 2 from overlying lithofacies 3, the latter possessing the clast fabric signature of a D A (dilatant) type deformation till although it was originally deposited as a discontinuous diamicton within a glaciofluvial sequence, probably as a hyperconcentrated flow, and appears to have been at least partially derived from underlying materials by glaciotectonic cannibalization. Lithofacies 4 is a glaciofluvial deposit comprising two coarseningupward sequences of gravel and diamicton. These facies have been overprinted with G B glaciotectonite and D A?B (dilatant to non–dilatant) deformation till structures and clast fabrics recording a vertical progression towards more pervasively deformed material. The sequence is capped by lithofacies 5, a two–tiered deformation till possessing the characteristics of D A and D B horizon subglacial tills previously reported from Icelandic glacier snouts. The whole sequence comprising lithofacies 2–5 represents a gravel outwash/deformation till continuum displaying variable strain signaturesproduced in response to stress induced by the overriding of Skalafellsjokull during the Little Ice Age. These signatures are dictated by the sediment rheology and a vertical strain profile for the sediment pile during glacier overriding is reconstructed. 相似文献
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对南极大气温室气体CO_2(含δ~(13)C-CO_2和δ~(18)O-CO_2)、CH_4和N_2O长期测值进行比较分析。结果表明,南极是全球大气温室气体浓度(CO_2稳定同位素丰度值)随纬度分布变化中的最低(高)区域。南极大气温室气体浓度值变化趋势、年增长率与全球整体上一致,但在具体数值上存在差异。南极CO_2平均年增长率(1958—2014年)为(1.43±0.59)mg·L~(–1)·a~(–1),低于同期赤道(1.51±0.72)mg·L~(–1)·a~(–1),但1980—2014年和2000—2014年年增长率均高于南半球中纬度地区。δ~(13)C-CO_2和δ~(18)O-CO_2丰度趋势揭示了化石燃料排放和全球尺度过程对CO_2的影响,但南极是受影响最小的区域。1983—2014年南极CH_4平均增长率为(6.2±4.9)μg·L~(–1)·a~(–1),低于北半球中纬度(6.5±5.6)μg·L~(–1)·a~(–1)而高于赤道(5.6±5.3)μg·L~(–1)·a~(–1)和南半球中纬度(6.1±4.9)μg·L~(–1)·a~(–1),这与CH_4人为排放增强主要在北半球中纬度地区而显著被OH氧化在赤道和中纬度地区的事实是吻合的。南极N_2O平均年增长率为(0.87±0.15)μg·L~(–1)·a~(–1)(2005—2013年),与南半球中纬度地区接近但低于北半球而高于赤道地区。 相似文献
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The Nova Basin contains an upper Miocene to Pliocene supradetachment sedimentary succession that records the unroofing of the Panamint metamorphic core complex, west of Death Valley, California. Basin stratigraphy reflects the evolution of sedimentation processes from landslide emplacement during basin initiation to the development of alluvial fans composed of reworked, uplifted sections of the basin fill. 40 Ar/39 Ar geochronology of volcanic units in middle and lower parts of the sequence provide age control on the tectonic and depositional evolution of the basin and, more generally, insights regarding the rate of change of depositional environments in supradetachment basins. Our work, along with earlier research, indicate basin deposition from 11.38 Ma to 3.35 Ma. The data imply sedimentation rates, uncorrected for compaction, of ~100 m Myr−1 in the lower, high-energy part to ~1000 m Myr−1 in the middle part characterized by debris-flow fan deposition. The observed variation in sediment flux rate during basin evolution suggests that supradetachment basins have complex depositional histories involving rapid transitions in both the style and rate of sedimentation. 相似文献
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Jean Goslin Jean-Louis Thirot Olivier Noël & Jean Francheteau 《Geophysical Journal International》1998,135(2):700-710
Among the mantle hotspots present under oceanic areas, a large number are located on—or close to—active oceanic ridges. This is especially true in the slow-spreading Atlantic and Indian oceans. The recent availability of worldwide gravity grids and the increasing coverage of geochemical data sets along active spreading centres allow a fruitful comparison of these data with global geoid and seismic tomography models, and allow one to study interactions between mantle plumes and active slow-spreading ridges. The observed correlations allow us to draw preliminary conclusions on the general links between surficial processes, which shape the detailed morphology of the ridge axes, and deeper processes, active in the upper mantle below the ridge axial domains as a whole. The interactions are first studied at the scale of the Atlantic (the Mid-Atlantic Ridge from Iceland to Bouvet Island) from the correlation between the zero-age free-air gravity anomaly, which reflects the zero-age depth of the ridge axis, and Sr isotopic ratios of ridge axis basalts. The study is then extended to a more global scale (the slow ridges from Iceland to the Gulf of Aden) by including geoid and upper-mantle tomography models. The interactions appear complex, ranging from the effect of large and very productive plumes, almost totally overprinting the long-wavelength segmentation pattern of the ridge, to that of weaker hotspots, barely marking some of the observables in the ridge axial domain. Intermediate cases are observed, in which hotspots of medium activity (or whose activity has gradually decreased) located at some distance from the ridge axis produce geophysical or geochemical signals whose variation along the axis can be correlated with the geometry of the plume head in the upper mantle. Such observations tend to preclude the use of a single hotspot/ridge interaction model and stress the need for additional observations in various plume/ridge configurations. 相似文献
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气流输送对乌鲁木齐市PM10、PM2.5和PM1.0质量浓度的影响 总被引：2，自引：0，他引：2
应用聚类分析法,对乌鲁木齐市2009-2010年逐日气流72 h后向轨迹按季节进行分类,结合对应时段的PM10、PM2.5和PM1.0观测数据,分析了不同气流输送轨迹对研究区3粒径段气溶胶浓度的影响.结果表明:冬季,气流对研究区气溶胶的搬运、稀释作用明显,气溶胶浓度平均值与对应气流移动速度成反比;春季,流经沙漠区的气流分组对应气溶胶浓度平均值偏高,且气溶胶谱分布向粗模态移动;夏季,大气清洁,携带城市气溶胶的西北气流对研究区气溶胶浓度平均值影响较大,未携带外源物质的几组气流流速与气溶胶浓度基本呈负相关;秋季,研究区受外源气溶胶影响不大,且气流对污染物的输送、稀释作用也不强烈,各分组气溶胶浓度差别不大. 相似文献
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Weikang Yang Jianfang Qiao Olivier Combreau Xingyi Gao Wenqin Zhong 《Journal of Arid Environments》2002,51(4):625
Display-site selection by houbara bustards was studied in Mori, Xinjiang, China during the breeding seasons from April to June 2000. Most of the habitats chosen for displaying were short sub-shrubby and open areas close to high shrub patches. The displaying males clearly prefer low covered areas and avoid densely covered and high vegetation sites. The vegetation density and number of plant species at display sites were significantly lower from that at randomly selected sites. The average distance to the closest shrub patch was significantly shorter at display sites than at random sites. Plant species richness, vegetative density, vegetative cover and distance to the shrub patches are possibly the most important factors that determined the display-sites selection of houbara bustard. 相似文献
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Nest and feeding behaviour patterns were compared between two sympatric species, the bushy-tailed gerbilSekeetamys calurusand the golden spiny mouseAcomys russatus, in order to assess nest site and food as possible resources of competition. The way the species interact under laboratory conditions was also compared. WhileS. calurusused a nest into which they removed bedding material, only two out of sixA. russatusdid so, while in at least half of the studied cases they were found roosting outside of the nest inside the enclosure. When introduced into the same enclosure,S. caluruswas the dominant species and in five out of 12 casesS. calurusinhabited the nest abandoned byA. russatus, and in seven casesA. russatuswas found resting in the enclosure. UnlikeA. russatus,S. calurusaccumulated food inside its nest and also protected the food resource in the enclosure againstA. russatus. It seems that different nest and feeding behavioural patterns can reduce competition between these two sympatric species. 相似文献