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1.
The quantitative analysis of glass, ceramics and related silicate systems by means of energy dispersive X-ray fluorescence spectrometry is considered and problems arising from the selective absorption of X-rays in multi-element specimens are discussed. A computer programme written in FORTRAN and based upon a “semi-fundamental parameters” approach to the correction of matrix effects in glass and chemically similar materials is fully described. Model data are provided to enable the programme to be run and tested. An “empirical coefficients” computer programme for the quantitative analysis of silicate systems is outlined and the limitations of this type of programme are pointed out. The importance of adequate sample preparation prior to X-ray spectrometric analysis is stressed.  相似文献   
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Fragments of plastron and vertebrae from the Griman Creek Formation (middle Albian) at Lightning Ridge, New South Wales, extend the Australian record for chelid pleurodires back in time by over 50 my. Contemporaneous with the oldest known occurrences of chelids in Patagonia, this record indicates that during globally warm intervals, pleurodire distribution included high palaeolatitude locations. Although referred to Chelidae, the material shows no characters to enable more detailed taxonomic assessment and it is unclear whether known genera are represented. The diverse and prolonged history of chelids in South America and Australia indicates that the basal eupleurodiran divergence occurred deep in the Jurassic.  相似文献   
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敦煌壁画高保真数字化采集是其数字保护工作的重要基础。依据前期研究及自主研制的敦煌壁画色卡,对敦煌壁画高保真复制品数字采集工作中图像的色彩管理性能进行了研究,并与标准色卡Macbeth ColorChecker的色彩管理效果进行了主观对比评价。研究结果表明,相同拍摄条件下,自主研制的敦煌壁画色卡的色彩管理主观视觉评价结果优于标准色卡,且对于不同类型照明光源和不同偏色设定条件,自主研制的敦煌壁画色卡可以对偏色图像颜色进行有效校正。  相似文献   
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After almost five centuries of development in nautical charts depicting the Adriatic Sea, a systematic, complete hydrographic survey was carried out that resulted in the first modern nautical chart of the area. The survey, a coordinated operation undertaken jointly by Austrian, Neapolitan and British experts in 1818–1819, was the first scientific activity in the Adriatic region to be based on international cooperation. Until then, the gathering, processing and presentation of geographical data on Adriatic nautical charts were neither systematic nor institutionalized activities, so those charts could not serve as reliable, safe sources of different types of information for seafarers and others for whom spatial relations in coastal, island and sea regions were of primary importance. Given the quality and quantity of hydrographical and geographical content presented in the Carta di cabotaggio del Mare Adriatico (Coasting Chart of the Adriatic Sea), it immediately became an essential source of spatial information.  相似文献   
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短途旅游中心的引力范围研究——以南京市为例   总被引:6,自引:0,他引:6  
张燕  张洪 《人文地理》2001,16(3):89-93
短途旅游是我国目前很有发展潜力的一种旅游形式,为此,有必要建立短途旅游中心。此中心的引力范围可用心理距离与地理距离相结合来度量。从短途旅游者的角度来看,选择短途旅游的旅游目的地,主要受闲暇时间与经济条件的限制,因而,用游客从居住地到旅游目的地的往返途中所耗时间与在旅游目的地滞留时间之比,及短途旅游出行支出意愿二项定量指标,可动态地描述衡量短途旅游中心引力范围的距离尺度,并据此作出等值线图形式的引力范围图。最后分析了南京市作为短途旅游中心的大致引力范围、竞争对手的分布及潜在旅游者。  相似文献   
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Mesofossil assemblages from several Cretaceous and Cenozoic units across Australia and New Zealand provide new evidence of insect and annelid behaviour. The earliest scale insects (Diaspididae, Coccoidea) from Australasia are described and represented by three scale morphotypes. The mesofossil assemblages also reveal clitellate annelid cocoon morphotypes, three morphotypes of arthropod coprolites and several insect piercement structures on gymnosperm leaf or stem fragments, possibly related to feeding or more likely oviposition. This research offers a new avenue for detecting cryptic terrestrial invertebrate groups and their interactions, particularly with plants, in the fossil record. The fossils demonstrate that insect/invertebrate activity can be preserved and identified in mesofossil suites, that such traces and exoskeleton fragments are relatively common in acid-extracted mesofossil suites, and that recognizable categories occur on multiple landmasses and at various ages.  相似文献   
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The Eumeralla and Wonthaggi formations (Otway and Strzelecki groups, respectively: late Hauterivian to Albian) of Victoria, Australia, have yielded diverse dinosaur faunas. Here we report a set of unassociated isolated specimens from these units including teeth, dorsal vertebrae, ribs and osteoderms of an indeterminate ankylosaurian dinosaur.  相似文献   
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The occlusal surfaces of 298 permanent maxillary and mandibular molar teeth of prehistoric shellfish‐gatherer subjects from the Piaçaguera and Tenorio sites (4930 to 1875 BP), near the central‐northern coastline of São Paulo, Brazil, were examined for classification of macro‐wear stages. Molar tooth wear is an indication of masticatory activity and can be used in the estimation of age at death. The examination of visual and schematic aspects of occlusal macro‐wear used a visual chart proposed by Brothwell, which includes the three superior and inferior, left and right, permanent molars. Three examiners performed the macroscopic observations twice under the same conditions. The resulting age estimates were compared with previous information of age estimated by skeletal examination. A reduced intra‐ and inter‐observer variation was observed; all re‐examinations indicated discrepancies of less than two years for the upper and lower limit of the age range estimates. The procedure was also considered consistent with the skeletal method used for age estimation of human remains excavated in Brazilian archaeological shell mounds, with a discrepancy of less than 8.22 years between the upper and lower limits of estimates by both methods. Age classification by the occlusal molar wear may be a useful tool for the classification of archaeological findings, mainly when only fragmentary skeletal remains are excavated. The current results indicate that the application of the Brothwell chart for Brazilian archaeological series presented satisfactory results of consistency, and its expanded use may represent a relevant adjunct for research. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   
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