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21.
通过中国科学院东北地理与农业生态研究所(简称东北地理所)及其前身(长春地理研究所)自1978 年以来40 a的遥感基础理论与应用研究工作的回顾,以主持的国家与地方重要遥感研究项目为主线,首先展现了研究所在遥感队伍建设、人才培养、平台建设、光学与微波遥感基础理论与遥感应用研究、微波遥感器的设计与研制等方面的大量工作;然后结合东北地理所在东北地区及东北亚周边国家开展的研究工作,回顾了研究所在自然资源、土地利用/覆被变化、生态环境演变、灾害监测、农情遥感监测等领域所取得的成就;最后,根据国内外遥感科学与技术的应用发展态势和东北地区资源环境特征,对东北地理所遥感研究的发展前景和优先发展领域进行了展望。  相似文献   
22.
Morphology and mineralogical and geochemical compositions of freshwater ferromanganese nodules of Ol’khon Island (Sasa Formation) and Kulunda Plain (Lake Porozhnee) were studied. The study has shown rhythmic structures of the nodules, formed by macro- and microlayers with mineralized microflora. The layers are composed of either crystalline Mn mineral phases and finely dispersed Fe phases (Lake Porozhnee) or, on the contrary, crystalline goethite and X-ray amorphous Mn phases (Ol’khon Island). Separation of Mn and Fe mineral phases in the nodules proceeded during their formation and diagenesis. The freshwater nodules show both high (Lake Porozhnee) and low (Ol’khon Island) Mn/Fe ratios. The predominance of Fe phase in the Ol’khon nodules accounts for their high contents of REE, including Ce. The Porozhnee nodules grew, most likely, more rapidly, which is reflected in their low REE contents and Ce anomaly. The examined chemical and mineral compositions, textures, and structures of the nodules testify to the low-temperature hydrothermal source of their ore substance.  相似文献   
23.
民国时期中国地理研究所钩沉   总被引:1,自引:0,他引:1  
詹永锋  王洪波  邓辉 《地理研究》2014,33(9):1768-1777
中国地理研究所是中国地理学史上第一个地理学专门研究机关,1940年8月1日成立于重庆北碚,1950年4月以该所为基础成立中国科学院地理研究所筹备处。抗日战争时期抗战建国事业对地理人才的迫切需求、朱家骅对在中国发展地理学的大力提倡、管理中英庚款董事会息金收入的资金支持和近代以来地理学专门研究机构的缺失共同构成中国地理研究所成立的历史背景。成立后的中国地理研究所吸引了一批优秀的地理学者,开展了广泛的地理实地考察,撰写了丰富的地理著作,出版了多种地理读物,培养了众多的地理学人才,为中华人民共和国成立后中国现代地理学的发展奠定了坚实的基础。  相似文献   
24.
The postperovskite phase transition of Fe and Al-bearing MgSiO3 bridgmanite, the most aboundant mineral in the Earth's lower mantle, is believed to be a key to understanding seismological observations in the D″ layer, e.g., the discontinuous changes in seismic wave velocities. Experimentally reported phase transition boundaries of Fe and Al-bearing bridgmanite are currently largely controversial and generally suggest wide two-phase coexistence domains. Theoretical simulations ignoring temperature effects cannot evaluate correctly two-phase coexistence domains under high-temperature. We show high-pressure and high-temperature phase transition boundaries for various compositions with geophysically relevant impurities of Fe2+SiO3, Fe3+Fe3+O3, Fe3+Al3+O3, and Al3+Al3+O3 derived from the ab initio finite-temperature free energies calculated combining the internally consistent LSDA + U method and a lattice dynamics approach. We found that at ~ 2500 K, incorporations accompanied by Fe3+ expand the two-phase coexistence domains distinctly, implying that D″ seismic discontinuities likely arise from the phase transition of Fe2+-bearing bridgmanite.  相似文献   
25.
The semi-arid Sahel regions of West Africa rely heavily on groundwater from shallow to moderately deep(100 m b.g.l.)crystalline bedrock aquifers for drinking water production.Groundwater quality may be affected by high geogenic arsenic(As)concentrations(10μg/L)stemming from the oxidation of sulphide minerals(pyrite,arsenopyrite)in mineralised zones.These aquifers are still little investigated,especially concerning groundwater residence times and the influence of the annual monsoon season on groundwater chemistry.To gain insights on the temporal aspects of As contamination,we have used isotope tracers(noble gases,~3H,stable water isotopes(~2 H,~(18)O))and performed hydrochemical analyses on groundwater abstracted from tube wells and dug wells in a small study area in southwestern Burkina Faso.Results revealed a great variability in groundwater properties(e.g.redox conditions,As concentrations,water level,residence time)over spatial scales of only a few hundred metres,characteristic of the highly heterogeneous fractured underground.Elevated As levels are found in oxic groundwater of circum-neutral pH and show little relation with any of the measured parameters.Arsenic concentrations are relatively stable over the course of the year,with little effect seen by the monsoon.Groundwater residence time does not seem to have an influence on As concentrations,as elevated As can be found both in groundwater with short(50 a)and long(10~3 a)residence times as indicated by ~3He/~4He ratios spanning three orders of magnitude.These results support the hypothesis that the proximity to mineralised zones is the most crucial factor controlling As concentrations in the observed redox/pH conditions.The existence of very old water portions with residence times10~3 years already at depths of50 m b.g.l.is a new finding for the shallow fractured bedrock aquifers of Burkina Faso,suggesting that overexploitation of these relatively low-yielding aquifers may be an issue in the future.  相似文献   
26.
The Mastigitae is a small supertribe of ant-like stone beetles that currently includes nine extant and five extinct genera. Extinct taxa are known within tribes Clidicini and Mastigini; the latter with one genus discovered in Baltic amber. For the first time, a Mesozoic genus of the tribe Mastigini is described, Clidicostigus arachnipes Jałoszyński, Brunke and Bai, gen. et sp. nov., from Cenomanian Burmese amber. The new taxon shares an enlarged and spiny scape and pedicel with its extant relatives but has deep elytral grooves and a strongly elongate and asymmetrical maxillary palpomere IV; the beetle has also enormously elongate maxillary palps and legs. The elongation of appendages in combination with only moderately large eyes is postulated to have evolved as an adaptation to running quickly, with tactile and chemical senses predominating over sight. The mode of life of Clidicostigus might have been similar to that of extant Mastigini, especially of particularly slender South African species that run on the ground and climb bushes and trees in search of prey.  相似文献   
27.
本文记述了1933年叠溪地震后的调查、报道和研究,重点介绍了中国西部科学院的叠溪地震调查及其著述《四川叠溪地震调查记》。关于叠溪地震,这是第一次科学性的现场调查和第一篇学术报告,具有重要的学术参考价值。  相似文献   
28.
The latest Cretaceous continental vertebrate faunas of the wider Transylvanian area figured prominently in discussions concerning the Cretaceous–Paleogene Boundary (K-Pg) events when they were first described by Nopcsa between 1897 and 1929, because they were assumed to be late Maastrichtian in age. Subsequently their age was reconsidered as early Maastrichtian, and were thus regarded of lesser importance in understanding the K-Pg boundary events in Europe and worldwide. Moreover, Transylvanian continental vertebrate assemblages (the so-called ‘Haţeg Island’ faunas) were often lumped together as a temporally restricted assemblage with a homogenous taxonomic composition. Recent fossil discoveries and more precise dating techniques have considerably expanded knowledge of the Transylvanian vertebrate assemblages, their ages, and their evolution. A synthesis of the available stratigraphic data allows development of the first comprehensive chronostratigraphic framework of the latest Cretaceous Transylvanian vertebrates. According to these new data, expansion of continental habitats and emergence of their vertebrate faunas started locally during the latter part of the late Campanian, and these faunas continued up to the second half of the Maastrichtian. During this time, long-term faunal stasis appears to have characterized the Transylvanian vertebrate assemblages, which is different from the striking turnovers recorded in western Europe during the same time interval. This suggests that there was no single ‘Europe-wide’ pattern of latest Cretaceous continental vertebrate evolution. Together, the available data shows that dinosaurs and other vertebrates were relatively abundant and diverse until at least ca. 1 million years before the K-Pg boundary, and is therefore consistent with the hypothesis of a sudden extinction, although this must be tested with future discoveries and better age constraints and correlations.  相似文献   
29.
The Cawthron Institute Culture Collection of Micro-algae (CICCM) is a unique, nationally and internationally significant collection of 450 strains of approximately 100 micro-algae and 50 cyanobacteria species, both living and cryopreserved. The collection comprises 13 taxonomic classes and underpins research into the ecology and taxonomy of the isolates and the biotoxins they produce and their toxicity. The CICCM expanded significantly in the 1990s after a major harmful algae bloom event in the Hauraki Gulf, New Zealand. Since 2000, it has underpinned development of molecular detection tools and enabled development of new chemical testing methods for biotoxins in seafood. The tropical collection allows research into potential issues for New Zealand as the oceans warm, for example, the risks of ciguatera fish poisoning and palytoxins in seafood. Research results generated from isolates in the cyanobacterial collection have assisted national risk management regarding drinking water and informed the development of the New Zealand guidelines for managing cyanobacteria in recreational fresh waters. The actual living and cryopreserved micro-algae and cyanobacteria collection (without infrastructure) has a current estimated value of NZ$1.6 million.  相似文献   
30.
全面总结了中国地质科学院勘探技术研究所“十三五”期间在定向钻井技术及仪器、深部钻探技术与装备、海洋钻探技术与装备等方面取得的重要成果,主要包括:创新突破定向水平井钻井及中靶技术,助力海域天然气水合物第二轮试采实现了从“探索性试采”向“试验性试采”的重大跨越;牵头实施完成“松科2井”重大科学钻探工程,实现了理论、技术、工程、装备的重大突破;成功研发了首套国产深海井口吸力锚,解决了深海浅软地层井口支撑力不足的难题。同时,分析了目前存在的问题,并结合当前所面临的挑战,对“十四五”期间的业务发展进行了展望。  相似文献   
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