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11.
A group of Roman glass objects from the Bocholtz burial in the SW of Limburg (The Netherlands) was found to have been subject to varying degrees of degradation. Many of the 25 colourless glass objects were fragmented to pieces <0.1 cm (“sugared”), whereas the three transparent blue-green glass objects were in near-pristine state. Analyses using SEM, XRF and EDS revealed that the fragmentation was the direct result of the intense leaching of Na2O from the glass structure and its replacement with water. The resulting gel layers with low-Na2O contents and large amounts of water are sensitive to cracking when they dry out. Thin-walled glass appears to be less sensitive to cracking from the resulting stress than thick-walled glass. Local differences in the moisture regime during burial also influence the severity of the glass degradation. Glass with low concentrations of CaO seems to be the most sensitive to this form of degradation. The typical blue-green Roman glass is less sensitive as it generally has considerably higher concentrations of CaO.  相似文献   
12.
J. HARA  N. TSUCHIYA 《Geofluids》2005,5(4):251-263
Sodic alteration assemblages including clinoptilolite, mordenite, analcime and Na‐montmorillonite were locally observed in sediments in the eastern part of the Hachimantai geothermal region, northeast Japan. This study investigated the mechanisms of sodic enrichment in the sediments during alteration. Kinetic results for water/rock interaction experiments are reported here. Batch‐type experiments were conducted at 150–250°C under saturated vapor pressure. Pyroclastic rocks dissolved incongruently in these experiments, and the solubility and dissolution rates among elements varied as follows: the apparent steady‐state concentrations of major elements are Si > Na ? K > Ca > Al and the order of the dissolution rates is Si > Al > Na ? K > Ca. Na had the highest steady‐state concentration and fastest dissolution rate of the alkali and alkali earth metal ions. Based on surface analysis of plagioclase, dissolution was effected via a reaction layer of Na‐montmorillonite on the mineral surface. Additionally, a reaction model constructed based on the experimentally observed reaction mechanism quantitatively explains the dissolution behavior. These results show that Na‐montmorillonite can be precipitated by pyroclastic rock/meteoric water interactions without seawater involvement: the Na is derived from the host rocks.  相似文献   
13.
青铜器锈蚀结构组成及形态的比较研究   总被引:5,自引:1,他引:4  
采用X射线衍射(XRD)、扫描电镜(SEM)、X射线电子能谱(EDS)和金相显微镜(OM)等方法,分析比较了染有“粉状锈”与未染“粉状锈”的典型青铜残片的锈蚀产物的矿物组成、腐蚀层分层结构及金相组织。结果发现,未染有“粉状锈”的青铜样品腐蚀层一般分为二层,外层是二价铜化合物,合金组织中未见α (α δ)组织,锈蚀产物中不含碱式氯化铜;而染有“粉状锈”的青铜样品都含有碱式氯化铜,其断面腐蚀层分三至四层,且每层锈体的结构和元素组成各不相同,在靠近合金基体层的锈层中发现了大量的CuCl存在。结果表明,青铜文物表面锈蚀覆盖层的致密性、空气中的湿度及锈层中CuCl层状分布的存在,是青铜器表面“粉状锈”形成和发展的根本原因。  相似文献   
14.
J. HARA  N. TSUCHIYA 《Geofluids》2009,9(1):24-38
Hydrothermal water–(pyroclastic) rock interactions were examined using flow-through experiments to deduce the effect of mass transport phenomena on the reaction process. A series of experiments were conducted over the temperature range 75–250°C, with a constant temperature for each experiment, and at saturated vapour pressure, to estimate the apparent rate constants as a function of temperature.
Based on the chemistry of analysed solutions, the water–rock interaction in the experiments was controlled by diffusion from the reaction surface and by the existence of a surface layer at the rock–fluid interface, which regulated the chemical reaction rate. The reaction progress depended to a high degree on flow velocity and temperature conditions, with element abundances in the fluid significantly affected by these factors. Mass transport coefficients for diffusion from the rock surface to the bulk solution have been estimated. Ca is selectively depleted under lower temperature conditions ( T  < 150°C), whereas Na is greatly depleted under higher temperature conditions ( T  > 150°C), and K reaction rates are increased when flow velocity increases. Using these conditions, specific alkali and alkali earth cations were selectively leached from mineral surfaces. The 'surface layer' comprised a 0.5–1.8 mm boundary film on the solution side (the thickness of this layer has no dependence on chemical character) and a reaction layer. The reaction layer was composed of a Si, Al-rich cation-leached layer, whose thickness was dependent on temperature, flow velocity and reaction length. The reaction layer varied in thickness from about 10−4 to 10−7 mm under high temperature/low fluid velocity and low temperature/high fluid velocity conditions, respectively.  相似文献   
15.
16.
The results of a minero-petrographic and isotopic study carried out on the marbles of statues and architectural elements belonging to several buildings on the “Hadrian's Villa” site (the so-called Canopus, the Peschiera, the Sala dei Pilastri Dorici and the Serapeum) are presented here as part of an ongoing archaeometric project which considers the determination of the provenance of all the marble decorations of the Villa complex. Analytical data indicate the prevailing presence of marmor lunense and the use of Pentelic and Thasian marbles for architectural elements in a few parts of the Sala dei Pilastri Dorici, the Peschiera and the Serapeum; no significant use is made of Proconnesian marble, probably the most inexpensive of the time. Analysis of sculptures from the Canopus showed that those of the Tiber and Nile gods were made of Parian marble, the Caryatids and Telamons of Pentelic marble and the Amazons of the precious white Dokymaean marble.  相似文献   
17.
This paper presents evidence for severe lead contamination among children of samurai families living in a castle town in Edo period Japan (1603–1867). Excavated rib bones were analyzed by atomic absorption, and soft X-ray roentgenograms of long bones were taken. The median values of lead concentration in the bones of children 3 years of age and under(1241.0 μg Pb/g dry bone) and 4–6 years of age (462.5 μg Pb/g dry bone) were significantly higher than those of adult males (14.3 μg Pb/g dry bone) and females (23.6 μg Pb/g dry bone) (p < 0.001). In addition, that of children over 6 years of age (313.0 μg Pb/g dry bone) was significantly higher than those of adult males (p < 0.01) and adult females (p < 0.05). The median value of lead in the bones of children 3 years of age and under was over fifty times higher than that of their mothers (adult females). Hypertrophy was seen in the long bones of five samurai children. In this area, lead lines or lead bands were distinguished by soft X-ray roentgenogram. Samurai children suffered from severe lead contamination in Edo period Japan. When the mothers were nursing their children, the children might have ingested their mother’s white lead non-selectively.  相似文献   
18.
To claim that Hayden White has yet to be read seriously as a philosopher of history might seem false on the face of it. But do tropes and the rest provide any epistemic rationale for differing representations of historical events found in histories? As an explanation of White's influence on philosophy of history, such a proffered emphasis only generates a puzzle with regard to taking White seriously, and not an answer to the question of why his efforts should be worthy of any philosophical attention at all. For what makes his emphasis on narrative structure and its associated tropes of philosophical relevance? What, it may well be asked, did (or could) any theory that draws its categories from a stock provided by literary criticism contribute to explicating problems with regard to the warranting of claims about knowledge, explanation, or causation that represent those concerns that philosophy typically brings to this field? Robert Doran's anthologizing of previously uncollected pieces, ranging as they do over a literal half‐century of White's published work, offers an opportunity to identify explicitly those philosophical themes and arguments that regularly and prominently feature there. Moreover, White's essays in this volume demonstrate a credible knowledge of and interest in mainstream analytic philosophers of his era and also reveal White as deeply influenced by or well acquainted with other important philosophers of history. White thus invites a reading of his work as philosophy, and this volume presents the opportunity for accepting it as such.  相似文献   
19.
Istanbul in the late nineteenth century grew to be a hub of the so‐called “white slave trade”, the trafficking of women predominantly from the Eastern Habsburg provinces to brothels from South America to East Asia. As a strong movement to suppress this trafficking grew in Europe, the Habsburg authorities’ incapability to suppress the trade endangered Austria‐Hungary’s standing in the Eastern Question, that is, its attempt to play a significant role in the Ottoman territories. The article investigates how contemporary discourses on gender, imperialism and nationalism combined to turn the issue of Austrian prostitutes in Istanbul into an issue that was strongly contested especially between the Ottoman authorities and the Habsburg diplomats at the beginning of the twentieth century.  相似文献   
20.
基于旅游行为的旅游目的地空间层次与管理   总被引:1,自引:0,他引:1  
王昕  陈婷 《人文地理》2009,24(6):107-110
关于旅游目的地的空间研究比较丰富,视点主要在于经济与地理空间。但是,旅游业是市场导向非常明显的行业,从旅游行为角度研究旅游目的地的空间层次更具有现实意义,对指导旅游目的地的开发和管理更具有操作性。本论文从旅游行为导向、管理方便性角度,融入社区理念,提出了新的旅游目的地解读,将其划分为三个空间层次,即游览服务区、社区服务区和社会服务区,并分析了它的空间层次结构关系和主要要素。论文最后从规范管理角度提出管理层次与关系。  相似文献   
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