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81.
As the criterion used by archaeologists for determining early white porcelain is quite ambiguous, the origin of Chinese white porcelain remains a point of disagreement. In this study, we systematically investigate 61 typical Xing porcelains of the late Northern dynasties to the early Sui dynasty (550–600 CE) using spectrophotometer, X-ray fluorescence (XRF), scanning electron microscopy (SEM), and X-ray powder diffraction (XRD), and analyze the differences between early white porcelain and celadon of Xing kiln in terms of their whiteness and raw materials characteristic. The results show that early white porcelain is a new type of ware that differs from celadon, which can be distinguished by whiteness, with a whiteness greater than 8% being early white porcelain and a whiteness less than 8% being celadon. It is assumed that the ancient potters created the whiter wares based on celadon by improving the glaze and selecting new raw materials for the body, but the production of this type of ware was short lived and subsequently refined in the Sui dynasty (581–618 CE) owing to the limited improvement in whiteness.  相似文献   
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This article aims at presenting and discussing the strategies for updating the finite element numerical modeling of stone masonry arch bridges using operational modal analysis. The study comprehended three bridges: two old ones, the St. Lázaro and the Lagoncinha bridges, and a recently constructed bridge in Vila Fria, Portugal. Updating of the bridge models is performed by comparing the numerical and experimental modal parameters. Three-dimensional detailed numerical models are used to perform modal analysis of the bridges. Experimental modal identification of the bridges is based on the measurement of their acceleration responses during normal operation. The assigned material properties are also based on available results obtained from in situ and laboratory tests and on the results of visual inspection and historical research carried out for both old bridges.  相似文献   
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Abstract

A consistent access to food is paramount for humans at individual and group level. Besides providing the basic nutritional needs, access to food defines social structures and has stimulated innovation in food procurement, processing and storage. We focus on the social aspects of food storage, namely the role of cooperation for the emergence and maintenance of common stocks. Cooperative food stocks are examined here as a type of common-pool resource, where appropriators must cooperate to avoid shortage (i.e. the tragedy of commons). ‘Food for all’ is an agent-based model in which agents face the social dilemma of whether or not to store in a cooperative stock, adapting their strategies through a simple reinforcement learning mechanism. The model provides insights on the evolution of cooperation in terms of storage efficiency and considering the presence of social norms that regulate reciprocity. For cooperative food storage to emerge and be maintained, a significant dependency on the stored food and some degree of external pressure are needed. In fact, cooperative food storage emerges as the best performing strategy when facing environmental stress. Likewise, an intermediate control over reciprocity favours cooperation for food storage, suggesting that concepts of closed reciprocity are precursors to cooperative stocks, while excess control over reciprocity is detrimental for such institution.  相似文献   
84.
于璐 《收藏家》2015,(2):3-10
2014年11月10日,APEC会议在北京召开,与此同时,由文化部、国家文物局与陕西、甘肃、宁夏、青海、新疆、河南六省区人民政府联合主办,中国国家博物馆承办的大型文物展览——《丝绸之路》于11月6日在北京中国国家博物馆开幕。展览汇集了来自全国16个省区市44家文博单位的490余件文物珍品,  相似文献   
85.
In this article, I explore the parallel responses of two groups of colonial subjects who were confronted with the institutional changes that occurred in the context of Enlightenment ideas in eighteenth-century Mexico: creole clerics headed by the Jesuit Francisco Javier Clavijero; and native religious men who petitioned to colonial authorities and the Crown for additional spaces for the education of indigenous men. I explore some of the interactions between creole clerics—often referred to as creole patriots—and native elites in the schools of central Mexico, and efforts by indigenous noble men to broaden the opportunities for natives to join the ranks of the Church and to receive a higher education. To this end, I build on the scholarship that has made evident how the hegemonic program of Bourbon reforms, which was inspired by the Enlightenment, was not a top-down plan implemented successfully and equally across the continent but rather a series of contested interpretations. This article contributes to the recent shift in the scholarship on the Enlightenment that acknowledges cross-cultural global exchanges by arguing that certain groups of natives in central Mexico, and a particular group of American-born clerics, participated actively in building a pragmatic version of the Enlightenment that responded to their local realities and contributed to a globalized understanding of enlightened ideas.  相似文献   
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After the Second World War, there were estimated to be around 20 million half-orphans in Europe. In Germany alone, 5.3 million soldiers killed in action left behind approximately 1.2 million widows, nearly 2.5 million half-orphans and about 100,000 complete orphans. This article examines how men and women from various social strata in western and eastern Germany remember their fathers who died in the war and in what way he has been stored in the family's collective memory. The analysis focuses on 30 life-history interviews with men and women from eastern and western Germany with various social and religious backgrounds, all of whom were born between 1935 and 1945 and had little or no memory of their fathers. The following questions are relevant: what memories did children have of their fathers, and what images of them were related by mothers and relatives? What individual, political, social and memory-cultural factors characterise a child's memory of her or his father? The article also analyses trans-generational transmissions and conflicts of how the father's past is remembered.  相似文献   
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In 1665, Robert Hooke published his major work in microscopy, Micrographia, a defense of experimental philosophy. The following year, Margaret Cavendish, Duchess of Newcastle, published at her own expense a treatise and a novel that undermined the basis of this new science. The dispute broke out at the initiative of the Duchess, in the context of a vast controversy about the legitimacy and the efficiency of optical instruments in natural philosophy. All the figures of the dual are used, except one: the counterattack. Cavendish, indeed, was alone on the battlefield. Is it possible to call a dual a battle with only one combatant? This particular case of dispute that stops owing to the shortage of combatants is the subject of this article.  相似文献   
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