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1.
In today’s world, the innovation of science and technology has become the key support for improving comprehensive national strength and changing the mode of social production and lifestyle. The country that possesses world-class scientific and technological innovation cities maximizes the attraction of global innovation factors and wins a strategic initiative in international competition. Based on the urban zip code geodatabase, an evaluation system of urban innovation with the perspective of innovation outputs, and the spatial evolutionary mode, concerning the structure of innovation space of Shanghai and Beijing from 1991 to 2014, was developed. The results of the research indicated that the zip code geodatabase provided a new perspective for studying the evolving spatial structure of urban innovation. The resulting evaluation of the spatial structure of urban innovation using the urban zip code geodatabase established by connecting random edge points, was relatively effective. The study illustrates the value of this methodology. During the study period, the spatial structure of innovation of Shanghai and Beijing demonstrated many common features: with the increase in urban space units participating in innovation year by year, the overall gap of regional innovation outputs has narrowed, and the trend towards spatial agglomeration has strengthened. The evolving spatial structure of innovation of Shanghai and Beijing demonstrated differences between the common features during the 25 years as well: in the trend towards the suburbanization of innovation resources, the spatial structure of innovation of Shanghai evolved from a single-core to a multi-core structure. A radiation effect related to traffic arteries as spatial diffusion corridors was prominent. Accordingly, a spatial correlation effect of its innovation outputs also indicated a hollowness in the city center; the spatial structure of innovation of Beijing had a single-core oriented structure all the way. Together with the tendency for innovation resources to be agglomerated in the city center, the spatial correlation effect of innovation outputs reflected the characteristics of the evolutionary feature where “rural area encircles cities”. The innovation spatial structure of Shanghai and Beijing have intrinsic consistency with the spatial structure of their respective regions (Yangtze River Delta urban agglomeration and Beijing-Tianjin-Hebei metropolitan region), which suggested that the principle of proportional and disproportional distribution of a city-scale pattern of technological and innovational activities is closely related to its regional innovation pattern. 相似文献
2.
K. Kawasaki D. T. A. Symons R. M. Coveney Jr . 《Geophysical Journal International》2007,171(2):594-602
Palaeomagnetic results are reported from the metalliferous Stark black shale in the Upper Pennsylvanian (Missourian/Kasimovian) Kansas City Group. Palaeomagnetic analysis of 400 specimens from 28 sites gives a characteristic remanent magnetization in 17 sites of the shale that yields a Late Mississippian to Middle Pennsylvanian palaeopole at 32.2°N 128.5°E (dp = 4.7° and dm = 8.8°). The observed palaeomagnetic age is slightly older than the host rock, indicating that the mineralization of the Stark Shale has, excluding recent alteration, a primary sedimentary or syngenetic origin. The reason for the slightly older age is likely due to trace modern hematite that slightly steepens the remanence inclination. The large oval of 95 per cent confidence is interpreted to be caused by clay–magnetite aggregates that formed during sediment transport and the biasing effect of the gentle palaeocurrent at each site acting on the large aggregates. Therefore, the scattered distribution of the site mean remanence declinations found for the Stark Shale is evidence of a detrital remanent magnetization that is formed by primary sedimentary processes with an enriched metallic content and not remagnetization with mineralization by secondary hydrothermal processes. 相似文献
3.
Ni-Mo-PGE-Au-rich ores in Chinese black shales and speculations on possible analogues in the United States 总被引：22，自引：0，他引：22
Molybdenum-rich black shales from the Cambrian of south China contain sulfide beds with >2 wt.% Mo, >2 wt.% Ni and 200–700 mg/T each for Au, Pt and Pd. Similar deposits occur in Canada. In the U.S. Midwest, Paleozoic black shales contain an extensive Mo anomaly and sporadic enrichments for Pt group elements, suggesting the presence of Ni-Mo-PGE-Au sulfide deposits like those being mined in China. 相似文献
4.
R.L. Anderson I. Ratcliffe H.C. Greenwell P.A. Williams S. Cliffe P.V. Coveney 《Earth》2010,98(3-4):201-216
Water-based drilling fluids are increasingly being used for oil and gas exploration, and are generally considered to be more environmentally acceptable than oil-based or synthetic-based fluids. Unfortunately, their use facilitates clay hydration and swelling. Clay swelling, which occurs in exposed sedimentary rock formations, can have an adverse impact on drilling operations and may lead to significantly increased oil well construction costs. Minimizing clay swelling is therefore an important area attracting a large amount of interest from both academia and industry. To effectively reduce the extent of clay swelling the mechanism by which clay minerals swell needs to be understood so that efficient swelling inhibitors may be developed. Acceptable clay swelling inhibitors must not only significantly reduce clay hydration, but must also meet increasingly stringent environmental guidelines while remaining cost effective. The development of these inhibitors, which are generally based upon water soluble polymers, therefore represents a challenge to oilfield geochemistry. This review aims to provide a comprehensive understanding of the mechanism by which clay minerals swell and what steps have been taken in the development of effective and environmentally friendly clay swelling inhibitors. 相似文献
5.
Binhe?GuEmail author Claire?L.?Schelske Michael?F.?Coveney 《Aquatic Sciences - Research Across Boundaries》2011,73(3):317-330
The purposes of this study were to assess if Lake Apopka (FL, USA) was autotrophic or heterotrophic based on the partial pressure
of dissolved carbon dioxide (pCO2) in the surface water and to evaluate factors that influence the long-term changes in pCO2. Monthly average pH, alkalinity and other limnological variables collected between 1987 and 2006 were used to estimate dissolved
inorganic carbon (DIC), pCO2 and CO2 flux between surface water and atmosphere. Results indicated that average pCO2 in the surface water was 196 μatm, well below the atmospheric pCO2. Direct measurements of DIC concentration on three sampling dates in 2009 also supported pCO2 undersaturation in Lake Apopka. Supersaturation in CO2 occurred in this lake in only 13% of the samples from the 20-year record. The surface-water pCO2 was inversely related to Chl a concentrations. Average annual CO2 flux was 28.2 g C m−2 year−1 from the atmosphere to the lake water and correlated significantly with Chl a concentration, indicating that biological carbon sequestration led to the low dissolved CO2 concentration. Low pCO2 and high invasion rates of atmospheric CO2 in Lake Apopka indicated persistent autotrophy. High rates of nutrient loading and primary production, a high buffering capacity,
a lack of allochthonous loading of organic matter, and the dominance of a planktivorous–benthivorous fish food web have supported
long-term net autotrophy in this shallow subtropical eutrophic lake. Our results also showed that lake restoration by the
means of nutrient reduction resulted in significantly lower total phosphorus (TP) and Chl a concentrations, and higher pCO2. 相似文献
6.
Seamus Coveney A. Stewart Fotheringham 《International journal of geographical information science》2013,27(7):1191-1211
Digital elevation model (DEM) elevation accuracy and spatial resolution are typically considered before a given DEM is used for the assessment of coastal flooding, sea-level rise or erosion risk. However, limitations of DEMs arising from their original data source can often be overlooked during DEM selection. Global elevation error statistics provided by DEM data suppliers can provide a useful indicator of actual DEM error, but these statistics can understate elevation errors occurring outside of idealised ground reference areas. The characteristic limitations of a range of DEM sources that may be used for the assessment of coastal inundation and erosion risk are tested using high-resolution photogrammetric, low- and medium-resolution global positioning system (GPS)-derived and very high-resolution terrestrial laser scanning point data sets. Errors detected in a high-resolution photogrammetric DEM are found to be substantially beyond quoted error, demonstrating the degree to which quoted DEM accuracy can understate local DEM error and highlighting the extent to which spatial resolution can fail to provide a reliable indicator of DEM accuracy. Superior accuracies and inundation prediction results are achieved based on much lower-resolution GPS points confirming conclusions drawn in the case of the photogrammetric DEM data. This suggests a scope for the use of GPS-derived DEMs in preference to the photogrammetric DEM data in large-scale risk-mapping studies. DEM accuracies and superior representation of micro-topography achieved using high-resolution terrestrial laser scan data confirm its advantages for the prediction of subtle inundation and erosion risk. However, the requirement for data fusion of GPS to remove ground-vegetation error highlighted limitations for the use of side-scan laser scan data in densely vegetated areas. 相似文献
7.
Seamus Coveney 《International journal of geographical information science》2013,27(3):467-483
Airborne LiDAR (light detection and ranging) data are now commonly regarded as the most accurate source of elevation data for medium-scale topographical modelling applications. However, quoted LiDAR elevation error may not necessarily represent the actual errors occurring across all surfaces, potentially impacting the reliability of derived predictions in Geographical Information Systems (GIS). The extent to which LiDAR elevation error varies in association with land cover, vegetation class and LiDAR data source is quantified relative to dual-frequency global positioning system survey data captured in a 400-ha area in Ireland, where four separate classes of LiDAR point data overlap. Quoted elevation errors are found to correspond closely with the minimum requirement recommended by the American Society of Photogrammetry and Remote Sensing for the definition of 95% error in urban areas only. Global elevation errors are found to be up to 5 times the quoted error, and errors within vegetation areas are found to be even larger, with errors in individual vegetation classes reaching up to 15 times the quoted error. Furthermore, a strong skew is noted in vegetated areas within all the LiDAR data sets tested, pushing errors in some cases to more than 25 times the quoted error. The skew observed suggests that an assumption of a normal error distribution is inappropriate in vegetated areas. The physical parameters that were found to affect elevation error most fundamentally were canopy depth, canopy density and granularity. Other factors observed to affect the degree to which actual errors deviate from quoted error included the primary use for which the data were acquired and the processing applied by data suppliers to meet these requirements. 相似文献
8.
在过去３０年中美国科学家已经产生了一种倾向性看法，即认为金属矿床是大尺度地质作用的产物（例如板块构造和盆地卤水区域性迁移）．在这一时期内，矿业公司和科学家空前地致力于金矿床研究。除了国内金矿之外，他们还特别注意研究国外的矿床。流体包裹体、绝对年龄、稳定同位素研究、计算机模拟、遥感和地球物理方法已经成为广泛应用的技术手段。当今普遍研究的矿床课题范围很广泛：包括斑岩型矿床、密西西比盆地型矿床、金刚石岩管、深海块状硫化物矿床、含贵金属煤、矿化页岩和一些新矿床类型（例如奥林匹克坝型矿床，卡林型矿床和Ｎｉ－Ｍｏ－ＰＧＥ－Ａｕ硫化物矿床）。在未来十年内，有可能继续注意国外金属矿床和金矿的研究。新的重要矿床发现（尤其是在基底地体、海洋和国外）正拭目以待。与沉积盆地中流体的最近研究相比较，可以预料扩大环境研究也具有重要意义。与此同时，象类似于接受板块构造理论一样，地球深部创造性研究可以使矿床成因的理性认识有所突破。 相似文献
9.
The Stark metalliferous black shale is a member of the Dennis Formation, which is a cyclothemic limestone and shale unit in the Missourian (Upper Pennsylvanian) Kansas City Group. Paleomagnetic analysis of 96 specimens from 7 sites indicates that the characteristic remanent magnetization of the Stark Shale yields a Late Mississippian to Early Pennsylvanian age. This age is close to, but slightly older than, the Middle Pennsylvanian host rock age and implies that the metalliferous content of the shale is syngenetic in origin. 相似文献
10.
Hyper-capitalism in global information and communication technology (ICT) markets during the late 1990s created a new global production network, shaped by multinational corporations, international capital flows, and a flourishing of high-tech entrepreneurship. Each of the cities considered here benefited substantially from this growth, but their positions as nodes in the ICT global production network differed markedly, as did their ability to appropriate the value they generated. In Dublin, value creation was based largely on inward technology and capital flows, although indigenous Dublin-based software companies did demonstrate their ability to compete internationally. ICT development in Helsinki and Tel Aviv drew more strongly on the local knowledge base, and benefited from changes in national regulatory and political conditions. In Helsinki, public and private R&D investments supported the highly effective globalisation strategy of Nokia to create a strongly localised, vertically-integrated and strongly specialised sector. Value creation in the more diverse Israeli ICT sector was also based primarily on locally developed technology, university R&D and the commercialisation of technology developed initially for military applications. By the end of the 1990s, the resulting ICT node in Tel Aviv was grounded in the local knowledge-base, technologically diverse, strongly entrepreneurial and globally oriented. 相似文献