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1.
正Introduction The amount of the total dissolved salts(TDS)in most of the salt brines on northern Tibet is relatively lower.So the effective brine concentration technique is needed for lithium,boron and potassium extraction from these brine 相似文献
2.
Yegor D. Sinelnikov Ganglin Chen Robert C. Liebermann 《Physics and Chemistry of Minerals》1998,25(7):515-521
Polycrystalline specimens in the CaTiO3–CaSiO3 perovskite system have been hot-pressed in a 2000-ton uniaxial split-sphere apparatus (USSA-2000) at pressures up to 15 GPa
and temperature of 1550°C, for the compositions CaTiO3, Ca(Ti0.75Si0.25)O3, Ca(Ti0.5Si0.5)O3. For the specimens with the bulk densities within 1% of the X-ray density, compressional and shear wave velocity measurements
have been conducted using ultrasonic interferometry. The measured adiabatic bulk moduli (K
s
) for the CaTiO3 and Ca(Ti0.5Si0.5)O3 perovskites are 175(1) and 188(1) GPa and shear moduli (G) of 106(1) and 109(1) GPa. In situ X-ray diffraction studies at high pressure and temperature resulted in isothermal values
for K
0 of 170(5) and 185(5) GPa, respectively. For the unquenchable CaSiO3 perovskite, elasticity theory and systematics were used to predict K
0=212(7) GPa and G
0=112(5) GPa; this shear modulus is 37% less than that for (Mg,Fe)SiO3 perovskite, suggesting that CaSiO3 perovskite cannot be ignored in modeling the composition of the Earth’s lower mantle.
Received: 27 June 1997 / Revised, accepted: 25 November 1997 相似文献
3.
正1 Introduction Lithium and its compounds as national strategic resources are extensively used in national defense,industrial and agricultural production.As we know,the salt lakes in the western of China are famous for its high 相似文献
4.
Military uses of groundwater: a driver of innovation? 总被引：1，自引：0，他引：1
Military need has been a positive driver to the development of the modern day, and now mature, science of hydrogeology. The important synergy between geology and water supply was appreciated by military men in the mid-nineteenth century but the first real test of this learning only took place in the First World War. German, British and American geologists then mapped water resources and the potential for exploiting groundwater in Belgium and northern France. Technical innovations included deployment of rapid drilling techniques and the promotion of well screens for use in unconsolidated sediments. The mapping techniques were developed further during the Second World War when innovative remote mapping of enemy-occupied territory became an important planning tool to both Allied and German armies. Work in North Africa and other arid and semi-arid terrains promoted insight into the occurrence of groundwater in fresh-water aquifers little replenished by recharge. Mapping of hard rock basement-type environments in the islands of Jersey and Guernsey by German geologists was a concept new to the British Isles. Collectively, these varied initiatives provided part of the foundation for post-Second World War development of modern-day applied hydrogeology. 相似文献
5.
Sogdianite, a double-ring silicate of composition
( \textZr0. 7 6 \textTi0. 3 84 + \textFe0. 7 33 + \textAl0.13 )\Upsigma = 2 ( \square 1. 1 5 \textNa0. 8 5 )\Upsigma = 2 \textK[\textLi 3 \textSi 1 2 \textO 30 ] ( {\text{Zr}}_{0. 7 6} {\text{Ti}}_{0. 3 8}^{4 + } {\text{Fe}}_{0. 7 3}^{3 + } {\text{Al}}_{0.13} )_{\Upsigma = 2} \left( {\square_{ 1. 1 5} {\text{Na}}_{0. 8 5} } \right)_{\Upsigma = 2} {\text{K}}[{\text{Li}}_{ 3} {\text{Si}}_{ 1 2} {\text{O}}_{ 30} ] from Dara-i-Pioz, Tadjikistan, was studied by the combined application of 57Fe M?ssbauer spectroscopy and electronic structure calculations. The M?ssbauer spectrum confirms published microprobe and
X-ray single-crystal diffraction results that indicate that Fe3+ is located at the octahedral A-site and that no Fe2+ is present. Both the measured and calculated quadrupole splitting, ΔE
Q, for Fe3+ are virtually 0 mm s−1. Such a value is unusually small for a silicate and it is the same as the ΔE
Q value for Fe3+ in structurally related sugilite. This result is traced back to the nearly regular octahedral coordination geometry corresponding
to a very symmetric electric field gradient around Fe3+. A crystal chemical interpretation for the regular octahedral geometry and the resulting low ΔE
Q value for Fe3+ in the M?ssbauer spectrum of sogdianite is that structural strain is largely “taken up” by weak Li–O bonds permitting highly
distorted LiO4 tetrahedra. Weak Li–O bonding allows the edge-shared more strongly bonded Fe3+O6 octahedra to remain regular in geometry. This may be a typical property for all double-ring silicates with tetrahedrally
coordinated Li. 相似文献
6.
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
7.
Recent academic debates about port competition have centered on the strategic responses of port authorities, operators, managers
and owners to the emergence of global supply chains. The competitive performance of a port authority or operator, given the
rise of the integrated logistics sector, depends increasingly on its strategic relationship to these supply chains and rather
less on traditional port competition factors such as hinterland size and physical infrastructure. However, there are few empirical
studies investigating the degree to which particular port actors are capable of inserting themselves into global supply chains.
In this article we ask what factors condition the supply chain strategies of port actors. We hypothesize that the strategic
supply chain choices of a port authority or operator are conditioned by the territorialized institutional framework in which
the dominant actors in a port operate. We apply these insights through a case study of the transformation of Dubai Port Authority,
and the rise of Dubai Ports World (DPW).
相似文献
| Peter V. HallEmail: |
8.
In the present paper, we propose a new method for the estimation of the variogram, which combines robustness with efficiency under intrinsic stationary geostatistical processes. The method starts by using a robust estimator to obtain discrete estimates of the variogram and control atypical observations that may exist. When the number of points used in the fit of a model is the same as the number of parameters, ordinary least squares and generalized least squares are asymptotically equivalent. Therefore, the next step is to fit the variogram by ordinary least squares, using just a few discrete estimates. The procedure is then repeated several times with different subsets of points and this produces a sequence of variogram estimates. The final estimate is the median of the multiple estimates of the variogram parameters. The suggested estimator will be called multiple variograms estimator. This procedure assures a global robust estimator, which is more efficient than other robust proposals. Under the assumed dependence structure, we prove that the multiple variograms estimator is consistent and asymptotically normally distributed. A simulation study confirms that the new method has several advantages when compared with other current methods. 相似文献
9.
Electron paramagnetic resonance (EPR) spectra of CO
3
3–
molecule-ions stabilized by Sc3+ in natural calcite were identified and studied at X-band frequencies and room temperature. The principal values of the g-tensor (g
xx= 1.9997, g
yy = 2.0030, g
zz = 1.9972) and the direction cosines of the g and A tensors for CO
3
3–
-Sc3+ center were found to be close to that for the well-known CO
3
3–
-Y3+ center. A quantitative comparison of different impurity contents in calcite samples and analysis of the intensities of forbidden transitions were used to identify Sc3+. An estimation of the unpaired electron spin density on the nuclei of paramagnetic centers confirms that both centers, CO
3
3–
-Sc3+ and CO
3
3–
-Y3+, have the same nature. 相似文献
10.
Dr. A. Rice 《Mineralogy and Petrology》1995,54(1-2):137-147
Summary Fine-scale igneous layering consisting of alternating bands of chromitite and plagioclase often occurs in the Bushveld Complex where it is commonly known as stringers. The origin of these features has been unclear but they do have both quantitative and qualitative characteristics of a type of microsegregation (compositional nonhomogeneity) known as solute banding which frequently occurs in solidifying industrial melts. The cause of solute banding is due to temperature fluctuations arising from unsteady convection in the melt which generates cotectic shifting at the solidification front, leading to alternating deposition of one phase, then another.
With 3 Figures 相似文献
Zusammenfassung Feiner magmatischer Lagenbau, der aus alternierenden Lagen von Chromitit und Plagioklas besteht, ist häufig im Bushveld zu beobachten und wird weithin als Stringers bezeichnet. Die Entstehung dieser Erscheinung war bisher nicht geklärt, aber sie zeigt sowohl quantitative wie qualitative Aspekte einer Art von Mikrosegregation (Inhomogenität der Zusammensetzung), die als Solute Banding bekannt ist und häufig in erstarrenden industriellen Schmelzen zu beobachten ist. Der Grund für Solute Banding liegt in Temperaturschwankungen, die auf ungleichmäßige Konvektion in der Schmelze zurückgeht. Letztere führt zu Verschiebung der kotektischen Positionen an der Verfestigungsfront, die schliesslich in alternierender Ablagerung der beiden Phasen resultiert.
With 3 Figures 相似文献
11.
12.
The thermoelastic parameters of synthetic Mn3Al2Si3O12 spessartine garnet were examined in situ at high pressure up to 13 GPa and high temperature up to 1,100 K, by synchrotron radiation energy dispersive X-ray diffraction within a DIA-type multi-anvil press apparatus. The analysis of room temperature data yielded K 0 = 172 ± 4 GPa and K 0 ′ = 5.0 ± 0.9 when V 0,300 is fixed to 1,564.96 Å3. Fitting of P–V–T data by means of the high-temperature third-order Birch–Murnaghan EoS gives the thermoelastic parameters: K 0 = 171 ± 4 GPa, K 0 ′ = 5.3 ± 0.8, (?K 0,T /?T) P = ?0.049 ± 0.007 GPa K?1, a 0 = 1.59 ± 0.33 × 10?5 K?1 and b 0 = 2.91 ± 0.69 × 10?8 K?2 (e.g., α 0,300 = 2.46 ± 0.54 × 10?5 K?1). Comparison with thermoelastic properties of other garnet end-members indicated that the compression mechanism of spessartine might be the same as almandine and pyrope but differs from that of grossular. On the other hand, at high temperature, spessartine softens substantially faster than pyrope and grossular. Such softening, which is also reported for almandine, emphasize the importance of the cation in the dodecahedral site on the thermoelastic properties of aluminosilicate garnet. 相似文献
13.
14.
Jutha Sunitsakul Attasit Sawatparnich Auckpath Sawangsuriya 《Geotechnical and Geological Engineering》2012,30(1):263-268
Unconfined compressive strength (UCS) of cement stabilized bases was collected from a number of highway construction projects
in Thailand. Results from the statistical analysis indicated that the most important factors affecting the UCS were the CBR
and the water to cement ratio. The UCS was however independent on the dry density. A statistical model was developed in the
study to predict the UCS of cement stabilized bases. A model was developed based on the following criteria: (1) the dry density
of the sample shall be greater than 95 percent of the maximum dry density based on the modified Proctor compaction, (2) samples
shall be soaked for at least 2 h prior to testing, and (3) the CBR shall be measured at 0.1 inch (2.5 mm) penetration. 相似文献
15.
The superdeep North Caspian, South Caspian, and Barents basins have their sedimentary fill much thicker and the Moho, correspondingly, much deeper than it is required for crustal subsidence by lithospheric stretching. In the absence of large gravity anomalies, this crustal structure indicates the presence under the Moho of a thick layer of eclogite which is denser than mantle peridotite. Crustal subsidence in the basins can be explained by high-grade metamorphism of mafic lower crust. The basins produced by lithospheric stretching normally subside for the first ～100 myr of their history, while at least half of the subsidence in the three basins occurred after that period, which is another evidence against the stretching formation mechanism. According to the seismic reflection profiling data, stretching can be responsible for only a minor part of the subsidence in the Caspian and Barents basins. As for the South Caspian basin, there has been a large recent subsidence event in a setting of compression. Therefore, eclogitization appears to be a realistic mechanism of crustal subsidence in superdeep basins. 相似文献
16.
Doklady Earth Sciences - Based on the data of atomic modeling, the different schemes of isomorphic incorporation of Cr3+ ions into the crystal structures of CaSiO3 and MgSiO3 were tested in the... 相似文献
17.
Simon A. Hunt Alex Lindsay-Scott Ian G. Wood Michael W. Ammann Takashi Taniguchi 《Physics and Chemistry of Minerals》2013,40(1):73-80
Orthorhombic post-perovskite CaPtO3 is isostructural with post-perovskite MgSiO3, a deep-Earth phase stable only above 100 GPa. Energy-dispersive X-ray diffraction data (to 9.4 GPa and 1,024 K) for CaPtO3 have been combined with published isothermal and isobaric measurements to determine its P–V–T equation of state (EoS). A third-order Birch–Murnaghan EoS was used, with the volumetric thermal expansion coefficient (at atmospheric pressure) represented by α(T) = α0 + α1(T). The fitted parameters had values: isothermal incompressibility, $ K_{{T_{0} }} $ = 168.4(3) GPa; $ K_{{T_{0} }}^{\prime } $ = 4.48(3) (both at 298 K); $ \partial K_{{T_{0} }} /\partial T $ = ?0.032(3) GPa K?1; α0 = 2.32(2) × 10?5 K?1; α1 = 5.7(4) × 10?9 K?2. The volumetric isothermal Anderson–Grüneisen parameter, δ T , is 7.6(7) at 298 K. $ \partial K_{{T_{0} }} /\partial T $ for CaPtO3 is similar to that recently reported for CaIrO3, differing significantly from values found at high pressure for MgSiO3 post-perovskite (?0.0085(11) to ?0.024 GPa K?1). We also report axial P–V–T EoS of similar form, the first for any post-perovskite. Fitted to the cubes of the axes, these gave $ \partial K_{{aT_{0} }} /\partial T $ = ?0.038(4) GPa K?1; $ \partial K_{{bT_{0} }} /\partial T $ = ?0.021(2) GPa K?1; $ \partial K_{{cT_{0} }} /\partial T $ = ?0.026(5) GPa K?1, with δ T = 8.9(9), 7.4(7) and 4.6(9) for a, b and c, respectively. Although $ K_{{T_{0} }} $ is lowest for the b-axis, its incompressibility is the least temperature dependent. 相似文献
18.
Just like in sedimentary stratigraphy, the volcanostratigraphic boundary is an important factor for constructing volcanostratigraphic framework. The fundamental factor of volcanostratigraphic boundaries is to classify the types and define their characteristics. Based on field investigation and cross-wells section analysis of Mesozoic volcanostratigraphy in NE China, 5 types of volcanostratigraphic boundaries have been recognized, namely eruptive conformity boundary(ECB), eruptive unconformity boundary(EUB), eruptive interval unconformity boundary(EIUB), tectonic unconformity boundary(TUB) and intrusive contacts boundary(ICB). Except ICB, the unconformity boundaries can be divided into angular unconformity and paraconformity. The time spans and signs of these boundaries are analyzed by using age data of some volcanic fields that have been published. The time spans of ECB and EUB are from several minutes to years. In lava flows, cooling crust is distributed above and below ECB and EUB; in pyroclastic flows, airfalls and lahars, a fine layer below these boundaries has no discernable erosion at every part of the boundary. EUB may be curved or cross curved and jagged. The scale of ECB/EUB is dependent on the scale of lava flow or pyroclastic flows. The time span of EIUB is from decades to thousands of years. There is also weathered crust under EIUB and sedimentary rock beds overlie EIUB. In most instances, weathered crust and thin sedimentary beds are associated with each other laterally. The boundary is a smooth curved plane. The scale of EIUB is dependent on the scale of the volcano or volcano groups. The characteristics of TUB are similar to EIUB’s. The time interval of TUB is from tens of thousands to millions of years. The scale of TUB depends on the scale of the basin or volcanic field. Both the lab data and logging data of wells in the Songliao Basin reveal that the porosity is greatly related to the boundaries in the lava flows. There is a high-porosity belt below ECB, EUB or EIUB, and the porosity decreases when it is apart from the boundary. The high-porosity belt below ECB and EUB is mainly contributed by primary porosity, such as vesicles. The high-porosity belt below EIUB is mainly contributed by primary and secondary porosity, such as association of vesicles and spongy pores, so the area near the boundary in lava flows is a very important target for reservoirs. 相似文献
19.
This paper argues that there is an immanent and evolving relationship between the prevailing form of taxation and the economic geographies of the state. Despite this, the geographic significance of taxation has been obscured by the language in which its historic transformation tends to be couched. Prevailing fiscal systems tend to be presented as essentially static – institutionally and spatially fixed and routinely inscribed within the fixed boundaries and territories of the ‘sovereign’ fiscal state. Any threat to, or change in the nature or geography of the fiscal state tends to be couched in terms of ‘crisis’ – of negative and discontinuous change. This paper contends that these related and essentially conservative discourses of fiscal geography mask the degree to which fiscal spaces are both multiple and continuously evolving. More importantly, it argues, this fluidity and multiplicity does not threaten the stability and viability of state form, but it is an essential process in its maintenance and reproduction. Running counter to the prevailing discourse of the ‘national economy’, the practice of fiscal geography is an under-analysed but key aspect of the historical evolution and transformation of the imagined geographies of economies. 相似文献
20.
Drowning accidents at beach in Japan are caused by rip currents. To reduce these accidents, a new technology that can detect rip currents and notify beachgoers by using the Internet of Things (IoT) and Artificial Intelligence (AI) was proposed. However, studies on the effect of visualizing rip currents or considering the effect of optimism bias have not been conducted. This study investigates if visualization of rip currents might help in preventing drowning accidents, while considering the effect of optimism bias. The participants were 90 Japanese beachgoers. They were asked to answer questions based on their knowledge of the beach and rip currents, their optimism bias regarding rip currents, and awareness with or without visualization. The results of the analyses suggest that despite optimism bias, the visualization of rip currents increases the tendency of beachgoers to perceive and avoid rip currents. As described above, it was found that by visualizing the rip current, beachgoers were able to perceive and avoid rip currents. In addition, an understanding of rip currents is positively related to the intent to avoid rip currents even when rip currents are visualized. Therefore, it is necessary not only to enhance the avoidance tendency by visualizing rip currents, but also to further enhance knowledge of beachgoers to deepen the understanding of rip currents including the danger associated and methods to avoid them.
相似文献