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991.
尹章才 《武汉大学学报(信息科学版)》2012,37(6):733-736
在柯拉斯尼模型的基础上,借助因特网通信体系的分层方法,提出了Web 2.0地图作为空间信息平台的双向传输体系,丰富和完善Web 2.0环境下的地图信息传递理论。 相似文献
992.
摘要本文主要阐述基于GIS的矿产资源可视化监测系统的设计与研究的技术路线。通过系统的建设,为矿产资源开发管理提供可靠的信息支撑和客观真实的数据依据。 相似文献
993.
《The Professional geographer》2012,64(1):22-36
Vaccination rates in Illinois schools are decreasing as more parents opt for nonmedical exemptions (NMEs). At the local scale, higher levels of exemptions affect herd immunity levels. Few studies have previously conducted or proposed methods to conduct local-scale spatial and temporal cluster pattern analysis. This study used vaccination exemption data from the Illinois School Board of Education’s annual Immunization School Survey for the 2003–2004 and 2013–2014 academic years. The Getis–Ord General G statistic was used to identify cluster detection by individual vaccine at the school level. The Getis–Ord Gi* statistic was used with two different parameter models to identify hot and cold spots. This study found that NMEs are highly clustered. More clusters of high and low NMEs were identified for the 2013–2014 academic year than for 2003–2004. The percentages of schools that were neither hot nor cold averaged 94.0 percent for the 2003–2004 school year and 78.7 percent for the 2013–2014 school year. NME rates in Illinois are rising. The increase in hot and cold spots is evidence that the polarity of vaccination choice is growing. As vaccination exemption rates continue to polarize U.S. society, it is essential for public health efforts to monitor and conduct local-level studies. Key Words: antivaccination, hot spot analysis, medical geography, nonmedical exemption, spatial statistics. 相似文献
994.
《The Professional geographer》2012,64(1):9-21
Desalination is an increasingly important water source for the sunny, arid city of El Paso, Texas. As the city’s population grows, El Paso Water, the city’s water utility, has had to drill deeper into the Hueco Bolson aquifer, a primary water source for El Paso. This deeper drilling into the Hueco Bolson, however, has yielded progressively more saline water. In response, El Paso Water and administrators from Fort Bliss jointly constructed a reverse osmosis desalination plant to protect the Hueco Bolson’s freshwater supplies and expand the city’s water sources. Reverse osmosis water desalination, however, is an expensive, energy-intensive process currently dependent on carbon-heavy fossil fuels. Solar energy, however, is an abundant, carbon-free energy source that could potentially reduce the energy costs and carbon footprint of the reverse osmosis desalination process. We hypothesize that building a solar microgrid that supplies El Paso’s desalination plant with energy in tandem with the regional grid will reduce the plant’s energy expenditures in the long term compared to solely buying energy from the regional grid. We used the Hybrid Optimization for Multiple Energy Resources (HOMER) model created by the National Renewable Energy Laboratory. The results suggest that a solar microgrid whose modules use one axis tracker could reduce the plant’s energy expenses. Key Words: desalination, solar energy, water resources. 相似文献
995.
Water-tank experiment on the thermal circulation induced by the bottom heating in an asymmetric valley 总被引:1,自引:0,他引:1
Water tank experiments were carried out to investigate the thermal convection due to the bottom heating in an asymmetrical valley under neutral and stably stratified approach flows with the Particle Image Velometry (PIV) visualization technique. In the neutral stratification approach flow, the ascending draft induced by bottom heating is mainly located in the center of the valley in calm ambient wind. However~with ambient wind flow, the thermal convection is shifted leeward, and the descending draft is located on the leeward side of the valley, while the ascending draft is located on the windward side. The descending draft is minorly turbulent and organized, while the ascending draft is highly turbulent. With the increase of the towing speed, the descending and ascending drafts induced by the mechanical elevation begin to play a more dominant role in the valley flow, while the role of the thermal convection in the valley airflow becomes limited. In the stable stratification approach flow, the thermal convection is limited by the stable stratification and no distinct circulation is formed in calm ambient wind. With ambient wind, agravity wave appears in the upper layer in the valley. With the increase of the ambient wind speed, a gravity wave plays an important role in the valley flow, and the location and intensity of the thermal convection are also modulated by the gravity internal waves. The thermal convection has difficulty penetrating the upper stable layer. Its exchange is limited between the air in the upper layer and that in the lower layer in the valley, and it is adverse to the diffusion of pollutants in the valley. 相似文献
996.
2002年10~11月在15°00′~27°40′N,121°30′~131°00′E的吕宋岛、台湾岛和琉球群岛以东的西北太平洋副热带环流区设测站121个,观测了该区表层和水柱中的叶绿素a质量浓度分布和光合浮游生物粒级结构。结果表明,观测海区秋季叶绿素a的质量浓度较低,变化幅度较小,变幅范围为0.039~0.271μg/dm3。台湾岛至琉球群岛以东的北部测区平均叶绿素a质量浓度高于吕宋岛以东的南部测区。叶绿素a含量的垂直分布在真光层内随深度的增加而增大,在真光层以下却随深度增加而降低。表层水的光合浮游植物细胞丰度较低,并以小粒径的硅藻占优势,细胞丰度约为103个/dm3。粒度分级结果表明,Pico级份的光合浮游生物占绝对优势(86%),Nano级份次之(11%),大细胞的Net级份所占比例最小(3%),呈现出微微型光合浮游生物在寡营养海区居重要地位的状况。 相似文献
997.
Marcelo C. L. Cohen Paloma Maria Pinto Camargo Luiz C. R. Pessenda Flávio Lima Lorente Adriana V. De Souza José Augusto Martins Corrêa José Bendassolli Marianne Dietz 《第四纪科学杂志》2021,36(6):1013-1027
The high sea-level stand during the mid-Holocene is a benchmark in mangrove dynamics along the north-east/south-east coast of Brazil and provides a reference point for landward and seaward mangrove migrations corresponding to changes in relative sea level (RSL). However, evidence of the impacts associated with RSL fall on the northern Brazilian coast is scarce. Multi-proxy data from the highest tidal flats of the Bragança Peninsula in northern Brazil revealed modern herbaceous areas were occupied by mangroves Rhizophora and Avicennia from ~6250 to ~5850 cal a bp , and only Avicennia between ~5850 and ~5000 cal a bp . The same tidal flats were vegetation-free between ~5000 and ~4300 cal a bp . A combination of a high sea-level stand (0.6 ± 0.1 m) at ~5000 cal a bp and a dry early–middle Holocene in the Amazon probably caused an increase in porewater salinity of tidal flats, which resulted in a mangrove succession from Rhizophora to Avicennia dominance. RSL fall accentuated this process, contributing to mangrove degradation between ~5000 and ~4300 cal a bp . RSL fall, and a wetter period over the past ~4300 cal a bp caused a mangrove migration from highest to lowest flats, followed by expansion of herbaceous vegetation on the highest flats. 相似文献
998.
This integrated study on the pressure–temperature–deformation‐time record of the Goszów light quartzites from the Młynowiec–Stronie Group (Sudety Mts., SW Poland) provides new data that improve our understanding of the structure and geodynamic development of the Orlica–Śnieżnik Dome (OSD) as a Gondwana‐derived unit involved in the formation of the Variscan orogen. The structural and metamorphic record of the Goszów light quartzites, when compared to the under‐ and overlying rock formations, indicates that the whole Młynowiec–Stronie Group in the eastern part of the Saxothuringian terrane functioned as a single, integral lithotectonic unit with no visible structural or metamorphic discontinuities. The sequence of structures and thermodynamic modelling indicate that the light quartzites underwent the same polyphase tectonometamorphic evolution as the adjacent rocks belonging to the Młynowiec–Stronie Group. The development of tight, N–S‐trending folds and axial penetrative metamorphic foliation was related to metamorphic progression from 500 °C to 640 °C at 6–7 kbar. Subsequently, under the retrogressive conditions below 540 °C, the foliation was reactivated as a result of subsequent N–S‐directed ductile shearing and extension. Therefore, the study of the light quartzites exemplifies the penetrative structures in the OSD, and the metamorphic foliation and N–S‐trending lineation are composite structures. The monazite metamorphic ages of ca. 364 Ma and 335 Ma may be related to the approximately E–W‐ and N–S‐oriented tectonic movements, respectively, which occurred during the amalgamation of the Saxothuringian terrane with Brunovistulia. In contrast, the previously unknown early Palaeozoic monazite age of ca. 494 Ma is interpreted as the protolith age of the light quartzites. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
999.
福建建阳井后钼矿地质特征及成因探讨 总被引:1,自引:0,他引:1
建阳井后钼矿位于闽西北隆起带东缘,浦城一永泰南北向构造岩浆活动带中部。矿床形成于燕山晚期,主要受区域上南北向断裂构造带控制的隐伏斑岩体控制。矿体以线脉一细脉及石英大脉型为主,围岩为中一晚元古代马面山群大岭组变质岩与加里东期二长花岗岩。 相似文献
1000.