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71.
The effect of carbonic anhydrase enzyme on the precipitation kinetics and phase transformations of calcium carbonate, and on the strength development of lime mortars has been investigated with saturated lime solutions, lime pastes and lime mortars under atmospheric conditions. The results clearly show that carbonic anhydrase catalyzes the reaction between carbon dioxide and aqueous lime, and increases the rate of calcium carbonate crystallization, the yield of the carbonation reaction and mortar strength at early ages. This is most likely a kinetic effect associated with the increased rate of carbonate ions supply to the solution by the enzyme. In addition, this enzyme favors the formation of stable calcite and significantly modifies its morphology by developing new crystal faces. These results suggest a novel approach for accelerating the hardening of lime mortars using carbonic anhydrase enzyme, which may offer a potentially novel approach with significant benefits on the applications of lime mortars in architectural heritage conservation as well as in construction.  相似文献   
72.
During the Upper Paleolithic, lithic variability is one of the most important keys to recognize hunter-gatherer behavior, technology, ecology, and social dynamics. The origin and expansion of Gravettian populations in Eurasia has been seen as one of the most critical episodes in human evolution, argued to be the first clear evidence of the so-called polymorphism among modern human populations. In the case of southern Iberian Peninsula, recent data have shown a new regional and diachronic organization for the Gravettian occupation in this region. Therefore, the interpretation of such variability is one of the most important questions, and functional analysis is a fundamental proxy to recognize human technological, settlement and ecological adaptations as major factors for this polymorphism. This study focused on lithic use-wear analysis of the Early Gravettian of Vale Boi (southern Portugal), in order to understand lithic technological organization and variability within and between occupations at the site. Results show similar patterns between assemblages, showing that different materials were worked at the site, although showing reduced time of work, low variability and percentage of pieces used. Unlike other Gravettian contexts in southern Iberia, the Early Gravettian from Vale Boi is characterized by some variability of backed points, marked by the predominance of bipointed double-backed bladelets. Functional analysis of the Early Gravettian lithic industries of Vale Boi provide a new insight to interpret human technology and settlement strategy during the onset of Upper Paleolithic industries in western Eurasia.  相似文献   
73.
山西古村镇类型及社会记忆符号系统研究   总被引:1,自引:0,他引:1  
社会记忆是依附于社会群体产生的一种趋同性的社会文化符号。本研究利用结构主义符号学的分析方法,通过“要素体-因子层-属性脉”的三维层次构建社会记忆的符号系统,基于中国传统社会生产、生活方式的视角,从地脉、人脉、文脉的“三脉”属性对古村镇的类型及特征进行解读,发现:①“农”型古村镇社会记忆的宜农宜居、望族乡贤、天人合一的三脉属性符号特征明显;②“商”型古村镇具有对外通达的地脉记忆,精致讲究的文脉记忆和名商名士的人脉记忆;③“军”型古村镇的社会记忆在据险扼要、防御之上、将军传奇的三脉属性特征更加突出;④“工”型古村镇具有矿藏丰富、炉旺风顺、匠人传奇的特色社会记忆的符号特征。  相似文献   
74.
卷轴是书画艺术的一种独特展示与收藏形式,卷轴书画画芯表面的折痕不仅影响展陈效果,而且降低了书画文物的保存寿命。为此,利用超景深显微镜和扫描电镜分析了卷轴书画折痕的微观结构,探讨了折痕产生的机理,并提出了相应的预防措施。结果表明:小直径收卷是书画产生折痕的重要原因之一;收卷直径越小,书画出现折痕的现象越明显。通过在地杆处加轴管以增大收卷直径,能够有效减少折痕和断裂的产生。该方法保持了中国传统卷轴书画的装裱形式,维持了书画的原貌,并能够有效保存书画展示的传统韵味。研究结果为探讨书画折痕产生的机理和防治对策研究提供科学依据。  相似文献   
75.
Abstract

This work proposes the term ‘naval elites’ in order to provide a new interpretation of social change in the eighteenth century from a comparative perspective. Naval elites, a social group formed by a part of the naval officer corps and midshipmen, are here defined as a historical instrument, the particular and intriguing features of which may be useful in the revision of some perspectives on social change. In particular, the authors analyse shifting power relationships through the reconsideration of naval patronage and bureaucracy, revisit the process of naval professionalization and the transformation of the concept of merit, and suggest that naval elites embodied new notions of social distinction and exclusiveness.  相似文献   
76.
This paper explores the potential of acoustics to interpret the prehistoric rock art of southern Andalusia (Spain). Tests undertaken in two areas, north of the Celemín river and the Bacinete area, will form the basis of our discussion. The results obtained at a selection of rock art sites show that the two key rock art sites, El Tajo de las Figuras and the large shelter at Bacinete, both with the majority of paintings in the earlier Laguna de la Janda style, had good resonance values. In contrast, at most of the other minor sites tested, the values for resonance were negative or insignificant, regardless of whether they were painted in Laguna de la Janda or schematic style. We conclude that the major rock art sites in southern Andalusia were chosen not only for their geological appearance and location in the landscape, but also for their acoustic properties.  相似文献   
77.
78.
This article contributes to the debate on macroeconomic management and capital account regulations in developing and emerging countries (DECs). It argues that the recommendation by neoclassical economists and international financial institutions (IFIs) to combine an inflation‐targeting regime with exchange rate management, whilst maintaining open capital accounts, is not only impossible but also potentially counterproductive. The article draws on extensive semi‐structured interviews with currency traders in Brazil and London to show that this is due to the particular way such a regime shapes central bank interventions in the money and foreign exchange markets and the destabilizing way these interventions interact with financial market expectations. The interview results also demonstrate that the guidelines issued by IFIs actually undermine, rather than aid, DEC central banks’ initial attempts to manage excessive exchange rate movements. These results support the long‐standing argument by heterodox economists and critical international political economists that DECs need to make the exchange rate an explicit instrument and goal of their macroeconomic policy and complement it with comprehensive capital account regulations to reduce the destabilizing impact of international capital flows. The interview results also give some concrete suggestions on how to achieve this.  相似文献   
79.
This paper investigates zoning in a cross‐border linear city that consists of two bordering towns. In each town, a local regulator has a say in the location of the local firm. We find that local regulators may use zoning strategically. The incentive to gain consumers from the other town, or not to lose local consumers, may push regulators to approve only locations for firms close enough to the frontier. When zoning is costly an asymmetric equilibrium may emerge: only one regulator resorts to zoning. In the case of towns of different sizes, the regulator of the larger town is the only one that zones in an asymmetric equilibrium.  相似文献   
80.
Landscape interpretation is needed for navigating and determining an orientation: with traditional cartography, interpreting 3D topographic information from 2D landform representations to get self-location requires spatial orientation skill. Augmented reality technology allows a new way to interact with 3D landscape representation and thereby facilitate the orientation of oneself in respect to the environment to determine goal location. This paper analyses if AR spatial landform improves the learner’s spatial orientation skill measured with the perspective taking/spatial orientation test by paired sampled t-tests. A workshop was conducted with 123 university students (63 treatment group, 60 control group) in which students had to identify locations and routes based on the interpretation of the relief, represented by AR. Results of the workshop showed an improvement in spatial orientation skill of 20.14 degrees average gain in the treatment group. Students who were not subject to the workshop (control group) did not improve their spatial orientation skill. The possibility of using free AR three-dimensional applications and exploit the potential of tablets and smart phones, which are widespread today, makes it possible to design and implement strategies for the development of spatial skills in formal teaching in the scope of Geography in higher education.  相似文献   
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