黄铜器表面着色方法的研究

在总结古代铜器表面处理的文献基础上一通过化学成膜探讨含锌32％－36％的黄铜试样表面着色的方法,通过调整和控制试液的浓度、温度、酸度及浸泡时间的实验,确定黄铜表面栗色膜形成的最佳条件。对表面形成的粟色膜用多种实验手段进行了测定,结果表明栗色股厚度约为8μm主要组成为Cu2O。并对化学过程中形色栗色膜的机理作了初步探体     

A study of parametric versus non-parametric methods for predicting paleohabitat from Southeast Asian Bovid astragali

Studies of the African members of the family Bovidae have demonstrated the feasibility of using linear discriminant analysis to predict paleoenvironment based on measurements from postcranial skeletal elements. The use of discriminant analysis depends upon adherence to certain assumptions about the data set. In certain cases, these assumptions are violated, thus reducing the confidence of the results. The research presented here introduces the use of the non-parametric recursive partitioning method as a test of the linear discriminant method for predicting habitat from a collection of modern Bovid astragali from Southeast Asia. This study also provides a critique of the previous African studies. The results indicate that a combination of the parametric and non-parametric methods provides the highest prediction accuracy for Southeast Asian Bovids, though the independent methods do test favorably; thus providing an additional tool for archaeologists and paleoanthropologists in this region.     

Marine shell dates and surface lithic assemblages on the west coast of South Africa

Archaeological surface finds are difficult to date. There are several useful methods, but each requires special circumstances and has one drawback or another. On the west coast of South Africa marine shell are abundant on surface sites but they are rarely dated because they are perceived to be in disturbed context and in questionable association with artefacts. This paper attempts to rectify this misconception and shows that, although far from perfect, a large suite of surface dates can shed as much light as excavated data. On the Vredenburg Peninsula they help refute the hypothesis that two economically and culturally distinct populations shared this pre-colonial landscape since 2000 BP.     

Torsional Wave in a Viscoelastic Layer over a Viscoelastic Substratum of Voigt Types

This article explores the dissipation and dispersion of torsional wave resulting from imperfection in elasticity in terms of internal friction, layer width between dissimilar homogeneous viscoelastic isotropic medium having Voigt-type viscosity. The closed forms solutions for the displacement in the upper layer and lower half space are obtained separately. The generalized torsional wave period equation is obtained and the angular frequency has been plotted against wave number for different values of relevant parametric variation and certain particular cases have been deduced. Dissipation and dispersion are analysed using two and three dimensional plots along with filled contour plots.     

A Multi-Method Approach to Reconstructing Occupational History and Activity Areas: A Case Study at the Formative Site of Tlalancaleca,Central Mexico

While surface collection constitutes an important component of field research at the site and regional levels, the association between surface and sub-surface materials needs to be examined through independent lines of evidence. This study employed manual bucket auger probing and soil geochemistry at the Formative site of Tlalancaleca, Central Mexico (800 b.c.–a.d. 250), to evaluate the results of surface collection and to understand the formation process of the anthropogenic landscape. The combined results at one of the largest architectural complexes at Tlalancaleca indicate that it was built during the Late Formative period (500–100 b.c.) and rebuilt during the subsequent Terminal Formative period (100 b.c.–a.d. 250), which is corroborated by radiocarbon dates. Moreover, the results suggest segregated uses of space such as cooking/storage, waste disposal, and craft production areas within the complex. Overall results demonstrate the effectiveness of this multi-method approach for reconstructing occupational history and activity areas.     

Evaluating effects of chemical weathering and surface contamination on the in situ provenance analysis of building stones in the Cuzco region of Peru with portable XRF

As the only type of instrument capable of determining artifact geochemistry in a wide variety of settings, portable X-Ray Fluorescence (PXRF) may be frequently utilized as probably the best option for collecting data when removal of objects in part or in whole is unfeasible. However, using PXRF in circumstances where sample selection and preparation diverge from standards developed for lab-based instrumentation requires assessing the impact of new and potentially limiting factors to establish the validity of the method in these new contexts. Here we examine the effects of surface contamination and chemical weathering on the ability to assess provenance of igneous building stones used in the Cuzco region of Peru. Surface contamination was assessed through comparing low-impact cleaning methods on diorite and andesite blocks, and weathering was examined by comparing weathered vs. fresh surfaces of samples from two andesite quarries. In general, the lightest elements were most impacted by contamination and weathering while measurements of many of the heavier elements commonly used in provenance studies were relatively unaffected. Concentrations of Pb and Zn were problematic in the urban context of Cuzco because of pollution. Ability to determine provenance of building stones within those limitations (i.e., the validity of this application of PXRF) was demonstrated in a preliminary study by comparing measurements from uncleaned, exposed building stones in the region to fresh quarry samples.     

铜及其合金的表面着色机理

根据表面着色的化学动力学原理论证了铜及铜合金表面人工仿古着色处理的某些必要过程。如为何要进行着色前的表面预处理;表面预处理的主要内容及着色反应的化学机理。并对目前众多的人工表面着色配方进行了归纳。     

甘肃拉卜楞寺壁画表面涂层材质分析

西藏壁画表面大多刷有保护涂层。据记载,其材质主要是桐油、牛胶或清漆等。但目前,对该涂层材质科学的研究却较少,不利于后期保护修复。为配合拉卜楞寺壁画保护修复项目,本研究以衰减全反射红外光谱法(ATR-FTIR)、核磁共振氢谱法(~1H-NMR)、热裂解-气相色谱-质谱联用(Py-GC-MS)技术等分析手段,对甘肃夏河拉卜楞寺弥勒佛殿、时轮学院主殿壁画的涂层进行了分析。结果表明,两处佛殿壁画涂层可确定是一种干性油,种类与桐油较接近。但由于西藏壁画在材料和工艺上的独特性,材料老化等因素,拉卜楞寺壁画涂层在组成和结构上,与现代桐油有一定差别,表现出一定的丰富性和复杂性。后期修复,可采用性质与西藏传统涂层材料接近的干性油,例如桐油,作为新的壁画表面涂层材料。     

地面核磁共振方法在石质文物保护中的应用

石质文物破坏问题不仅在于人为破坏和表面污染,更多来自自然因素对文物的破坏,例如,日晒雨淋、风沙吹蚀、地表水的冲刷、地震、地下水的侵蚀溶蚀。为对第六批全国重点文物保护单位阳华岩摩崖石刻露天石质文物病害进行探查,采用无损探测的地面核磁共振方法和探地雷达方法,直接找水的地面核磁共振方法成功探测出摩崖石刻依附岩体地层含水分布状况。探地雷达方法探测出依附岩山体内岩溶、裂隙的发育状况。两种方法探测结果发现,石刻依附岩体内岩溶、裂隙发育,部分区域岩溶裂隙带已成为地下水汇聚场所或流通通道,对阳华岩摩崖石刻构成了极为严峻的侵蚀威胁。两种方法解释结果互为验证,研究结果为阳华岩摩崖石刻的病害治理和保护提供了宝贵的基础资料。     

SPATIAL AUTOCORRELATION and EIGENFUNCTIONS OF THE GEOGRAPHIC WEIGHTS MATRIX ACCOMPANYING GEO-REFERENCED DATA

Gaining a better understanding of spatial data and a deeper meaning of spatial statistical results gleaned from geo-referenced data requires a more complete knowledge of properties of the underlying geometry. This paper addresses these two topics by further investigating important geometric features of spatial data. The importance of this work is expressed in the geographic information system literature regarding representations of geographic space, as well as various geographic literatures concerned with spatial statistical modelling. Answers to three questions are obtained here. One asks whether or not those eigenvectors associated with the three largest eigenvalues of a binary geographic weights matrix have natural interpretations. A second question asks whether or not the eigenvalues of a geographic weights matrix prove useful in understanding the sampling distribution for spatial autocorrelation in a given geographic landscape. A third question addresses the issue of spatial autocorrelation components of geo-refer-enced phenomena. The analysis summarized in this paper documents responses to these three questions. Empirical evidence is gleaned from both Canadian urban census tract data and the square tessellations of remotely sensed data. Afin ?obtenir une meilleure compréhension de données spatiales et un sens plus approfondi de résultats statistiques spatiaux découlant de données spatialisées, il faut une connaissance plus complète des propriétés de la géométrie sous-jacente. La présente étude porte sur ces deux sujets en étudiant plus avant des caractéristiques géométriques importantes des données spatiales. La pertinence de ce travail est confirmée par la littérature sur les systèmes ?information géographique concernant des représentations de ?espace géographique, ainsi que par divers courants de la littérature gégraphique portant sur la modélisation statistique spatiale. Des réponses À donneràtrois questions ont pu être obtenues dans ce travail. Tout ?abord ?on se demande si les vecteurs propres associe's aux trois plus grandes valeurs propres ?une matrice gégraphique binaire de pondération ont des interprétations naturelles. Une deuxième question portant sur les valeurs propres ?une matrice géographique de pondération concerne leur utilityé pour la compréhension de la distribution ?échantillonnage de ?auto-corrélation spatiale sur un paysage gégraphique données Une troisième question concerne le problème de la composition de ?autocorrélation spatiale présente dans des données spatialisées. L ‘analyse résumée dans la présente étude comporte des éléments de réponseaG ces trios questions. Une démonstration empirique est faite à partir de données du recensement urbain canadien à?échelle des secteurs, et à partir de la mosaïque carrée habituelle de données satellitaires. Mots-clés: Fonctions propres, Géometrie, données spatialisées, autocorrelation spatiale, statistique spatiale, partition de surfaces