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71.
This project follows on from an initial study of Celtic gold coins from the Middle Rhine/Moselle region, which was based on material found at the Martberg, a Late Iron Age/Roman sanctuary and settlement (River Moselle, western Germany; Bendall 2003 ). The earlier work was expanded to encompass over 100 examples of various other regional Celtic gold coinages from the collection of the Römisch‐Germanisches Zentralmuseum, Mainz. The alloy (Au–Ag–Cu) and trace element compositions (in particular Ni, Sb and Pt) were determined by EPMA and LA–ICP–MS, respectively, and their Pb isotope signatures were measured by LA–MC–ICP–MS. Of the 28 trace elements measured, only Ni, Sb and Pt were found to show meaningful variations and so only they are presented here. In particular, differences in the Pt/Au ratios between various groups of earlier coinage (imitations of Philippus and Alexander/Nike staters, Sch. 23 and some early Boian coins) on the one hand, and the majority of the Boian and the southern rainbow cup coinages on the other, indicate a significant difference in the gold sources exploited for these regional coinages. The Pb isotope data confirm previous conclusions that the contribution of gold to the total lead in the Au–Ag–Cu coin alloys can be detected, especially for coins with over 70% gold, and show that possible gold sources include both eastern Mediterranean and Alpine sources. Combining the Pb isotope data with the Pt/Au ratios allows the potential gold sources to be further differentiated.  相似文献   
72.
73.
This paper seeks to examine how federal financial support of academic scientists shapes their collaborative behavior. More specifically, it investigates two questions: (i) are there threshold sizes of federal grants that have effects on collaboration? and (ii) do the threshold sizes differ by discipline? To test and model these questions, this paper uses data collected in a 2004–2005 survey by the Research Valuing Mapping Project (a project based at Georgia Tech and led by Barry Bozeman) of 2,086 academically based research scientists and engineers. The analysis in this paper reaffirms the positive relationship between federal funding and collaboration seen in previous works, but the findings suggest that there is in fact a threshold effect—as the positive relationship has a diminishing influence. The findings of this paper are more limited with respect to how academic disciplines’ threshold levels differ. The results indicate a difference in the threshold levels between disciplines for three of the eight models.  相似文献   
74.
The transformation of yellow goethite into red hematite by heating has long been assumed for Palaeolithic red artefacts excavated close to fireplaces. However, this transformation is extremely rare. Using SEM–FEG–EDX, PIXE–PIGE, TEM and μXRD, we characterized the mineralogical and chemical compositions of four microsamples of colouring materials from the Mousterian layer B in the es‐Skhul rock‐shelter, from about 100 kya ago. For some colouring materials, the Mousterian people of es‐Skhul chose to gather remote yellow lumps for heating. Their significant transport distance provides evidence of the possible high cultural value of these colouring materials for transformation into red pigments.  相似文献   
75.
博物馆策展人的素质与能力是博物馆陈列展览特别是专题展览成功的关键因素之一.美国大都会艺术博物馆亚洲艺术部主任、国际著名博物馆策展人屈志仁先生以"忽必烈的时代"展为例指出:博物馆策展人应同时具备学者、艺术鉴赏家与展览组织者的素质与能力,通晓与展览有关的历史学、艺术史、文化史及文物与博物馆学等学科知识,组织、协调从研究策划...  相似文献   
76.
Y. LIU  G. CHI  K. M. BETHUNE  B. DUBÉ 《Geofluids》2011,11(3):260-279
The Red Lake mine trend, a deformation zone in the Archean Red Lake greenstone belt that hosts the world‐class Campbell‐Red Lake gold deposit, is characterized by abundant foliation‐parallel iron‐carbonate ± quartz veins with banded colloform‐crustiform structures and cockade breccias overprinted by silicification and gold mineralization. There is an apparent incompatibility between the cavity‐fill structures of the veins and breccias (typically developed at shallow crustal depths) and the upper greenschist to lower amphibole facies metamorphic conditions recorded in the host rocks (indicating relatively deep environments). This, together with the development of veins along the foliation plane, represents an enigmatic problem that may be related to the interplay between fluid dynamics and stress field. We approach this problem through systematic study of fluid inclusion planes (FIPs) in the vein minerals, including the orientations of the FIPs and the pressure–temperature conditions inferred from fluid inclusion microthermometry. We find that fluid inclusions in the main stage vein minerals (pregold mineralization ankerite and quartz and syn‐ore quartz) are predominantly carbonic without a visible aqueous phase, whereas many inclusions in the postore stage contain an aqueous phase. Most FIPs are subvertical, and many are subparallel to the foliation. High fluid pressure coupled with the high wetting angles of the water‐poor, carbonic fluids may have been responsible for the abundance of brittle deformation features. The development of subvertical FIPs is interpreted to indicate episodic switching of the maximum principal compressive stress (σ1) from subhorizontal (perpendicular to the foliation) to subvertical (parallel to the foliation) orientation. The subvertical σ1 is favorable for the formation of foliation‐parallel veins, as fractures are preferentially opened along the foliation in such a stress regime, the origin of which may be linked to the fluid source.  相似文献   
77.
Layered low permeability rock units, like shales, represent seals or ‘cap‐rocks’ in a variety of geological settings. A continuous increase in the fluid pressure gradients across a virtually impermeable rock layer will ultimately lead to hydro‐fracturing. Depending on the boundary conditions, such fracturing may lead to the formation of a set of sub‐parallel cracks oriented more or less perpendicular to the cap‐rock layer. In this article, we propose a new numerical model that describes interactions between multiple cross‐cutting fractures in an elastic low permeability rock layer. The width of each fracture and the spacing between them are modeled as a force balance between the fluid pressure and the elastic forces in the cap‐rock and between each fracture. The model indicates that the system of fractures evolves toward a spatially periodic steady‐state distribution with a fixed fracture spacing and aperture. The results are similar for incompressible and compressible fluids. The steady‐state conditions depend on only two dimensionless parameters, and the fracture spacing is only weakly dependent on the cap‐rock thickness. This is in contrast to fracturing produced by simple extension of an elastic rock layer beyond the fracture strength, in which case fracture spacing is proportional to layer thickness.  相似文献   
78.
Lead isotope compositions provide a direct means of assessing provenance. The lead contents in bronzes cannot be used to argue against lead isotopes. Any claim for the origin of the source material for the origin of Yin‐Shang bronzes must satisfy the measured lead isotope compositions. Thus far, only southern African sources are found to meet this criteria.  相似文献   
79.
This paper examines invention patents in the Crown of Aragon during the seventeenth century. Patents were granted by the Council of Aragon, the Royal Council responsible for political and legal issues arising in the Spanish territories belonging to the Crown of Aragon. The Council's functions in the area of patents arose out of the monarchy's interest in extending the validity of royal patents from Castile to Aragon in order to enhance its control over technical discoveries and developments, and to raise fresh revenues for the treasury. Both foreign and Castilian inventors applied for patents, which were immediately applicable, but the privileges they entailed were accepted only with difficulty by the Aragonese institutions. This reluctance severely curtailed the number of applications. Meanwhile, the Council's desire to cooperate with the monarchy led it eventually to define criteria for the grant of patents. However, the legal and institutional structure of the Crown of Aragon made it difficult for inventors to enforce and defend their rights. The lack of new patent applications to the Council in the later seventeenth century illustrates how the existence of a separate jurisdiction obstructed the consolidation of a patents system in the Crown of Aragon, hindering the spread of technical progress in Spain.  相似文献   
80.

This article deals with the early colonization of the Russian Barents Sea Coast (the so-called Murman Coast) in the middle of the 19th and early 20th century. It focuses mainly on the household economy and economic adaptation in the area by groups of Finnish, Russian, Karelian, Norwegian and Sami colonists. The opening up of the new territory by the colonists resulted partly in the employment of traditional methods of using natural resources and partly in the culture of these groups being transformed. Based on this, two different patterns of using natural resources were singled out within the ethnic groups that settled on the Murman Coast (western and eastern). These patterns were more suited to the new living conditions in each of the respective areas, and became the basis for different trends in the economic development of the Murman Coast.  相似文献   
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