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1.
Cryptocrystalline silicates from the Chadron Formation were widely used by prehistoric human groups in the Great Plains of North America. There are two documented quarry areas: Flattop Butte in Colorado and the White River Badlands of South Dakota. Cryptocrystalline silicates from these sources are visually indistinguishable, making it difficult to determine the sources of artefacts found at archaeological sites. In this investigation, neutron activation analysis is used to distinguish the two sources. This technique also identifies lithic material from the Clovis-age Eckles site in Kansas as being from Flattop Butte.  相似文献   
2.
本文通过考古实物的科学分析,认为早在西周时期胶东青铜技术便发展到了一定水平,战国后便发展到了较为成熟的阶段,大约自西周始,胶东青铜技术与中原便是大体同步发展了的.文章最后还将胶东青铜合金成分与《考工记·六齐》作了比较,并提出了“六齐”既不是生产经验的总结,也不是指导生产实践的工艺规范,而是一种试验资料的反映和归纳的观点。  相似文献   
3.
Galileo did not develop a systematic methodology but rather a methodical form which represents an essential part of the development of modern scientific thought. Keywords to the methodical form of Galileo's thought are: 1) The geometrization of the sciences (‘mathematization of nature’) - this refers especially to the explication of the methodological priority of a theory of measurement. 2) Argomento ex suppositione, that is, the coupling of the originally proof-theoretical distinction between analysis and synthesis to elements of a methodology of empirical science. 3) The axiomatic structure of mechanics that corresponds to the modern semantic theory conception and to constructivist conceptions of the philosophy of science. 4) A constructive (or instrumental) concept of experience, which replaces the Aristotelian concept of a phenomenal experience in the construction of physics.  相似文献   
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The study implements the performance-based analysis and design methodology to assess the seismic vulnerability of a coal-fired power plant and to optimally design its equivalent pendulum-type tuned mass damper system such that the direct losses are minimized. A building-specific total loss ratio is developed to link the component level losses with the total repair cost of the original structure. The optimal system configuration is finally derived for cases with the minimum loss. The study demonstrates a systematic way of achieving the optimal pendulum-type tuned mass damper design with considerations of uncertainties in earthquake inputs and the combined component level damages.  相似文献   
6.
Seismic assessment of gravity dams is generally carried out using time history analyses. Scaling of the motions is commonly used; however, in contrast to buildings, the performance of scaling procedures at predicting the mean and reducing the dispersion in engineering demand parameters (EDPs) is not known. The main goal of this study is to assess the performance of different scaling procedures in predicting seismic demands on dams. The performance regarding the prediction of the damage and the required number of motions for effective analysis was investigated. The results show that techniques commonly used for moment frames should not readily be applied to these structures.  相似文献   
7.
Controlled rocking heavy timber walls are designed to rock on their foundations in response to earthquakes. For regions of moderate seismicity, it is proposed that this rocking behaviour can be adequately controlled using only post-tensioning, even with a large force-reduction factor and no supplemental energy dissipation. This article presents a force-based design procedure for controlled rocking cross-laminated timber walls without supplemental energy dissipation, including a method for estimating higher mode effects. Fragility analyses of three prototype walls demonstrate that the procedure can limit the probability of collapse to <10% during a maximum considered earthquake in a region of moderate seismicity.  相似文献   
8.
This technical note presents a refined technique for photo‐documenting archaeological mortuary features using High Dynamic Range (HDR) imaging. Mortuary features in archaeological context can be complex and delicate given the wide variability in grave constructions and preservation of human skeletal remains. It is therefore critical to obtain the greatest detail possible when photo‐documenting these features. HDR techniques represent more contrast in photographs and provide greater detail across the DR of illumination within mortuary features—where complex arrangements of human remains can obscure or darken other elements or associated funerary objects, making them difficult to identify in traditional photographs. HDR can be employed with most standard digital single lens reflex cameras used for archaeological field projects, is easy to learn and employ (as described here), can be processed and produced with commonly used photo editing programs, and is ideal for use in unpredictable conditions that are often encountered with archaeological mortuary features and in field conditions. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   
9.
为了预防性保护和修复秦俑,必须掌握秦俑残片显微结构及其烧制环境、破损方式,从而为改善秦俑修复工艺、筛选修复材料提供基础,运用偏光显微镜对秦兵马俑残片中的一些矿物质(石英、长石、云母等)颗粒的分布形态和含量来分析陶土的成分结构、制作工艺、烧成气氛及原料来源等信息。结果表明,秦俑陶片主要成分为少量砂屑及大量粘土,而粘土为岩土矿风化的产物,秦俑残片裂痕较多的部位风化、酥粉痕迹明显。秦俑制作工艺以模为主,模、塑结合,并在粘土中添加了细砂,多于还原气氛中烧制而成。  相似文献   
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