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31.
32.
广西桂平博物馆藏东汉铜甑对于研究广西地区青铜器冶铸技术的发展具有重要的研究价值。但器物长期保存于潮湿环境中,矿化严重、保存状况较差,亟须保护修复。本研究应用X射线影像观察、金相显微镜、扫描电镜及能谱分析、模拟实验验证等方法研究了器物的铸造工艺、合金成分以及锈蚀产物成分。结果表明该器物为整体铸造成形,器物铸造时使用了轮制技术、刮板造型工艺以及铸后刻纹的工艺,箅部范块制作过程是用器身模翻制器身范后脱模,将器身模的圈足部分切下,然后在圈足泥模上刻出箅部型腔。在此基础上,遵循最低限度干预原则,力求将传统的文物修复手段与现代修复理念相结合,通过除锈、修补等保护修复措施后,不但提高了器物的整体稳定性,而且达到了可以展陈,发掘文物潜在价值的要求。 相似文献
33.
Aurora Higueras‐Milena Castellano Antonio M. Sáez Romero 《International Journal of Nautical Archaeology》2018,47(1):81-102
The area of La Caleta, north‐west of Cadiz, is a key location for studies of the relationship between the Phoenician city of Gadir and the ocean. The port channel and the small islets that characterize the area was one the busiest sectors of the city, and there are abundant underwater remains attesting to past commercial activities. The area also had an important religious role: two sanctuaries were located at the western end of the rocky promontories that surround the channel, and many items identified as offerings have been found. This article synthesizes previous research and provides an overview of the results of a recent project (2008–2010), which enables a thorough review of the development of the seascape and its use during the 1st millennium BC. 相似文献
34.
A lack of clear political commitment together with confusing rules and enforcement often characterize the institutional context of policy implementation and regulatory compliance in developing countries. By connecting such contextual features to existing models of policy implementation and regulatory compliance, we examine how regulatory factors are related to basic and proactive corporate environmental management practices in the Pearl River Delta region in China. Drawing on data derived from both a survey and in‐depth interviews, we show that a perception of clear political commitment to environmental protection across multiple government levels and units is positively associated with business efforts in basic environmental practices, regardless of the specific enforcement intensity. Nevertheless, a perception of clear political commitment is not related to proactive environmental practices. Conversely, a perception of policy ambiguity, in the form of confusing regulatory standards and enforcement, is negatively associated with corporate efforts in both basic and proactive environmental practices; yet, intensive inspections mitigate these negative associations with policy ambiguity. 相似文献
35.
2009—2011年,山东博物馆对山东临沂地区佛教造像碑进行了多次调查,与相关金石文献对比,可判断这批佛教造像碑多数为北齐遗物,少数晚至隋代。临沂佛教造像碑具体特点有:碑身柱体,四面等宽或两面略窄,南面为正方位;四面造像,多为两段式,上段雕刻龛像,下段刻铭或留白(也有雕刻龛像的);造像题材中维摩诘图组合别具一格,龙衔莲花图十分流行,龛楣龙与兽面组合图在临沂地区之外十分少见。临沂佛教造像碑形制、造像特征虽源自西部邻省和山东中部地区,但也有自身原创特色,唐代流行的龙虎塔图像当与其龛楣龙与兽面组合图有极深渊源。 相似文献
36.
K. Su J.‐P. Latham D. Pavlidis J. Xiang F. Fang P. Mostaghimi J. R. Percival C. C. Pain M. D. Jackson 《Geofluids》2015,15(4):592-607
Accurate simulation of multiphase flow in fractured porous media remains a challenge. An important problem is the representation of the discontinuous or near discontinuous behaviour of saturation in real geological formations. In the classical continuum approach, a refined mesh is required at the interface between fracture and porous media to capture the steep gradients in saturation and saturation‐dependent transport properties. This dramatically increases the computational load when large numbers of fractures are present in the numerical model. A discontinuous finite element method is reported here to model flow in fractured porous media. The governing multiphase porous media flow equations are solved in the adaptive mesh computational fluid dynamics code IC‐FERST on unstructured meshes. The method is based on a mixed control volume – discontinuous finite element formulation. This is combined with the PN+1DG‐PNDG element pair, which has discontinuous (order N+1) representation for velocity and discontinuous (order N) representation for pressure. A number of test cases are used to evaluate the method's ability to model fracture flow. The first is used to verify the performance of the element pair on structured and unstructured meshes of different resolution. Multiphase flow is then modelled in a range of idealised and simple fracture patterns. Solutions with sharp saturation fronts and computational economy in terms of mesh size are illustrated. 相似文献
37.
38.
Biodiversity and Environmental Change: Monitoring,Challenges and Direction edited by D. LINDENMAYER,E. BURNS,N. THURGATE and A. LOWE (eds), CSIRO Publishing,Melbourne, Australia, 2014, xiv + 624 pp,ISBN: 9780643108561 (hardback), AU$120.00
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CATE MACINNIS‐NG 《Geographical Research》2015,53(2):226-227
39.
Latent trajectory models for space‐time analysis: An application in deciphering spatial panel data
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Li An Ming‐Hsiang Tsou Brian H. Spitzberg Dipak K. Gupta J. Mark Gawron 《Geographical analysis》2016,48(3):314-336
This article introduces latent trajectory models (LTMs), an approach often employed in social sciences to handle longitudinal data, to the arena of GIScience, particularly space‐time analysis. Using the space‐time data collected at county level for the whole United States through webpage search on the keyword “climate change,” we show that LTMs, when combined with eigenvector filtering of spatial dependence in data, are very useful in unveiling temporal trends hidden in such data: the webpage‐data derived popularity measure for climate change has been increasing from December 2011 to March 2013, but the increase rate has been slowing down. In addition, LTMs help reveal potential mechanisms behind observed space‐time trajectories through linking the webpage‐data derived popularity measure about climate change to a set of socio‐demographic covariates. Our analysis shows that controlling for population density, greater drought exposure, higher percent of people who are 16 years old or above, and higher household income are positively predictive of the trajectory slopes. Higher percentages of Republicans and number of hot days in summer are negatively related to the trajectory slopes. Implications of these results are examined, concluding with consideration of the potential utility of LTMs in space‐time analysis and more generally in GIScience. 相似文献
40.
Characterization of a Historical Cannonball from the Fortress of San Juan De Ulúa Exposed to a Marine Environment
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M. Hernandez M. Hernandez‐Escampa C. Abreu J. Uruchurtu M. Bethencourt A. Covelo 《Archaeometry》2016,58(4):610-623
Metallurgical analyses and chemical characterizations were carried out on historical cannonballs from the Fortress of San Juan de Ulúa, Veracruz, México. Cannonballs dating from the 18th and 19th centuries share metallurgical characteristics similar to those of material coming from a shipment of ammunition found in the wreck of a sunken French ship from the battle of Trafalgar. The analyses show that the base material is grey cast iron with a carbon equivalent of 4.94 and a ferritic–perlitic matrix, in which the high phosphorus content has led to the formation of iron phosphide compounds in conjunction with a homogeneous distribution of carbon graphite flakes of Type C. In addition, corrosion products from samples revealed the presence of various crystalline iron compounds (X‐ray diffraction), mostly highly chlorinated iron compounds identified as akaganeite. X‐ray fluorescence identified various characteristics of the corrosion products as a function of the sampling depth. FT–IR spectroscopy revealed that the main difference between the corrosion products (internal and external) is determined by the number of organic species. Differential scanning calorimetry corroborated that these corrosion products are thermally stable compounds at elevated temperatures. 相似文献