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《Journal of Atmospheric and Terrestrial Physics》1984,46(6-7):509-515
Flux variations of high energy (E > 16 keV) electrons, measured by the energetic particle spectrometer onboard the geosynchronous satellite GEOS 2, have been compared to simultaneously observed electron density structures in the lower ionosphere, measured with the incoherent scatter facility EISCAT. The very localized E-region electron density enhancements caused by the precipitation allow a preliminary estimate of the location of the footpoint of the magnetic field line through GEOS 2. Various other results of the intercomparison are discussed. 相似文献
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Duncan McDonnell 《Australian journal of political science》2019,54(3):318-333
ABSTRACTFor over a decade, the Australian Political Studies Association (APSA) has maintained a list ranking journals into A*, A, B and C bands. However, we know little about how Politics scholars use and view the list. In this study, we firstly discuss the history of the APSA list, before then presenting the results of an original survey conducted in March 2017 with over 250 members of the discipline. While the APSA list seems to enjoy overall support, we find that there are concerns about its purpose, its assessment of journal quality and how it treats different subfields and methodologies. In the discussion section, we address some of the main criticisms that have been made of the list and offer a number of suggestions for revisions. These include widening the consultation process, making submissions to the ranking committee public and extending the range of journals included in the list. 相似文献
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Hugo Blake 《Post-Medieval Archaeology》2017,51(1):1-42
In memory of Ronald Coleman of Chapel Hill, Queensland, Australia (1938–2008)
SUMMARY: The Tuscan origin of the characteristic large oil jars found all over the world was confirmed by neutron activation analysis about 20 years ago, although some still call them Iberian storage jars. Our paper presents the unpublished analytical data and considers whose oil they contained. Italian records show that in the 18th century Montelupo despatched coppi (jars) down the River Arno to Lucca, where the best Italian olive oil was produced, and to Livorno (Leghorn), then the largest emporium in the Mediterranean for transit trade. In London, the jars became a familiar sight with different high and popular cultural meanings. 相似文献
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Borck C 《Berichte zur Wissenschaftsgeschichte》2002,25(2):107-120
Presents three brief case studies to show how cognition and psychic activity were explored as energetic and economic transactions in a variety of experimental settings. First, in the 1870's German psychiatrist Emil Kraepelin began a search for an objective measurement of cognitive performance in which he engaged for several decades. His investigations resulted in a graphic representation of cognitive efficiency, the Arbeitscurve, delineating numbers of additions per time interval in close resemblance to representations of machine efficiency. Second, at the turn of the century American nutrition scientist and agronomist Wilbur Olin Atwater convinced himself in a series of precision measurements that the human motor was a perfectly closed input-output system and that any mental surplus in the form of cognitive energy transformation did not count as contradictions to the principle of the conservation of energy. Third, at the beginning of the 20th century and on the basis of Atwater's results, German psychiatrist Hans Berger stipulated a special form of psychic energy for mediating between the principle of the conservation of energy and mental causality. Berger attempted to quantify psychic energy as one factor of brain metabolism. In the three cases of precision investigations into psychic life presented here, the experimental space of psychophysiology turned mental activity into a form of machine-like behavior. 相似文献
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The solubility of quartz has been measured in a wide range of salt solutions at 800°C and 0.5 GPa, and in NaCl, CaCl2 and CsCl solutions and H2O–CO2 fluids at six additional P–T conditions ranging from 400°C at 0.1 GPa to 800°C at 0.9 GPa. The experiments cover a wide range of compositions along each binary. At P–T conditions where the density of pure water is low (0.43 g cm?3), addition of most salts produces an enhancement of quartz solubility at low to moderate salt concentrations (salt‐in effect), although quartz solubility falls with further decrease in XH2O. At higher fluid densities (0.7 g cm?3 and greater), the salt‐in effect is generally absent, although this depends on both the cation present and the actual P–T conditions. The salt‐in effect is most readily produced by chloride salts of large monovalent cations, while CaCl2 only produced a salt‐in effect at the most extreme conditions of high‐T and low‐P investigated (800°C at 0.2 GPa). Under most crustal conditions, the addition of common salts to aqueous fluids results in a lowering of quartz solubility relative to that in pure water (salt‐out effect). Comparing quartz solubility in different fluids by calculating XH2O on the basis that all salts are fully associated under all conditions yields higher quartz solubility in solutions of monovalent salts than in solutions of divalent salts, absolute values are also influenced by cation radius. Quartz solubility measurements have been fitted to a Setchenow‐type equation, modified to take account of the separate effects of both the lowering of XH2O and the specific effects of different salts, which are treated as arising through distinct patterns of non‐ideal behaviour, rather than the explicit formation of additional silica complexes with salt components. Quartz solubility in H2O–CO2 fluids can be treated as ideal, if the solvation number of aqueous silica is taken as 3.5. For this system the solubility (molality) of quartz in the binary fluid, S is related to its solubility in pure water at the same P–T conditions, So, by: Quartz solubility in binary salt systems (H2O–RCln) can be fitted to the relationship: where salt concentration mRCln is expressed as molality and the exponent b has a value of 1 except under conditions where salting‐in is observed at low salt concentrations, in which case it is <1. Under most crustal conditions, the solubility of quartz in NaCl solutions is given to a good approximation by: We propose that quartz solubility in multicomponent fluids can be estimated from an extended expression, calculating XH2O based on the total fluid composition (including dissolved gasses), and adding terms for each major salt present. Our experimental results on H2O–NaCl–CO2 fluids are satisfactorily predicted on this basis. An important implication of the results presented here is that there are circumstances where the migration of a fluid from one quartz‐bearing host into another, if it is accompanied by re‐equilibration through cation exchange, may lead to dissolution or precipitation of quartz even at constant P and T, with concomitant modification of the permeability structure of the deep crust. 相似文献
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Julie Davidson Charlotte Jones Malcolm Johnson Deniz Yildiz Vishnu Prahalad 《Geographical Research》2023,61(4):429-442
Concerns about the decline in uptake of secondary geography education continue despite arguments supporting the value of geography education, the power of geographical thinking, and geography’s critical role in preparing students to deal with complex challenges. Already constrained by neoliberal politics of disadvantage, young people must plan and prepare for chaotic futures. Consequently, young people are becoming distressed and worried about their futures and feeling powerless as society fails to adequately address these issues. In this article, we ask what schools and universities can do as place-based public institutions to serve young people to effectively respond to eco-anxiety and build capacities to surf the unrelenting waves of change. We draw on journeys that brought three young doctoral candidates to study geography. From their stories, we sketch what a geographical education could offer in terms of relevance, practicality, and engagement with transformative system change. We think that under current world conditions, this is a moment to revive geography education and give it renewed purpose to encourage young people to develop skills and competences to tackle wicked problems. 相似文献
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沧州铁狮子结构健康监测系统研究及测试试验 总被引:2,自引:2,他引:0
沧州铁狮子结构健康监测的研究为我国室外大型铁质文物的保护起到了示范作用。针对文物本体保护原则和铁狮子特有的结构形式,提出了健康监测系统的设计指导思想,构造了系统的总体框架,深入研究了传感器与数据采集子系统,对传感器进行选型,优化配置数据采集硬件系统并运用LabVIEW开发了专用的数据采集系统软件;开发了数据管理子系统,运用SQLServer建立中心数据库,运用Delphi设计了数据管理的用户操作界面,开发了相应的数据处理分析程序;运用MATLAB开发了基于ANSYS的铁狮子结构专用有限元分析模块,并初步探讨了结构的安全评定方法;通过Delphi软件建立系统集成平台,统一协调沧州铁狮子健康监测各子系统共同运行,编制了包括结构分析软件ANSYS、MATLAB等在内的所有相应接口程序。在以上研究成果的基础上,进行了沧州铁狮子结构健康监测试验,试验验证了该系统的可靠性,结果表明试验监测数据能够反映结构基本性能。 相似文献
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There is no ambiguity in the existing empirical support for a GIUR as a robust predictor of mass lost from flakes through unifacial retouching. We demonstrate why the GIUR is a reliable method for inferring mass loss, in appropriate circumstances, and why it is a more powerful predictor of mass loss than touted competitors. We explain why Eren, M.I., Sampson's, G. [2009. Kuhn's geometric index of unifacial stone tool reduction (GIUR): does it measure missing flake mass? J. Archaeol. Sci.] arguments are faulty and why researchers should use the GIUR in preference to other methods of estimating the extent of unifacial retouch. 相似文献
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Thermohaline convection of subsurface fluids strongly influences heat and mass fluxes within the Earth's crust. The most effective hydrothermal systems develop in the vicinity of magmatic activity and can be important for geothermal energy production and ore formation. As most parts of these systems are inaccessible to direct observations, numerical simulations are necessary to understand and characterize fluid flow. Here, we present a new numerical scheme for thermohaline convection based on the control volume finite element method (CVFEM), allowing for unstructured meshes, the representation of sharp thermal and solute fronts in advection‐dominated systems and phase separation of variably miscible, compressible fluids. The model is an implementation of the Complex Systems Modelling Platform CSMP++ and includes an accurate thermodynamic representation of strongly nonlinear fluid properties of salt water for magmatic‐hydrothermal conditions (up to 1000°C, 500 MPa and 100 wt% NaCl). The method ensures that all fluid properties are taken as calculated on the respective node using a fully upstream‐weighted approach, which greatly increases the stability of the numerical scheme. We compare results from our model with two well‐established codes, HYDROTHERM and TOUGH2, by conducting benchmarks of different complexity and find good to excellent agreement in the temporal and spatial evolution of the hydrothermal systems. In a simulation with high‐temperature, high‐salinity conditions currently outside of the range of both HYDROTHERM and TOUGH2, we show the significance of the formation of a solid halite phase, which introduces heterogeneity. Results suggest that salt added by magmatic degassing is not easily vented or accommodated within the crust and can result in dynamic, complex hydrologies. 相似文献
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日本农协金融的早期发展概况及启示 总被引:2,自引:0,他引:2
日本农协金融作为合作金融的典型代表,是比较成功的农村金融服务体系.章简要地介绍了战后恢复时期日本农协金融的发展概况,介绍了日本政府为解决农民资金短缺而采取的支持和辅助农协金融发展的措施.日本农协金融对我国发展农村合作金融的启示:一是要加强农村金融立法,尽快出台《合作金融法》:二是要加大对农村金融的扶持力度,建议通过立法将农信社定位为国家扶植农业的工具,将农业发展银行的县级支行合并列农信社;三是祛除农信社的官办色彩,把农信社真正办成农民自己的合作金融组织,农民才是农信社的“主人”,信用社是为农民服务的“仆人”. 相似文献
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本文分析、总结了芬兰、荷兰和意大利三国公务员培训的共性和特点,提出了我国公务员培训工作可以借鉴的培训理念、培训模式和培训手段。 相似文献