几件西沙华光礁I号沉船遗址出水瓷器的保护研究

为了对8件西沙华光礁I号沉船遗址出水瓷器进行表面凝结物去除、脱盐清洗和残缺补全等保护处理,采用X射线衍射(XRD),对瓷器表面凝结物进行了成分分析;用三维视频显微镜对瓷器进行脱盐前、后的显微照相对比;对瓷器表面微孔内的物质,用扫描电镜分析(SEM)方法进行成分检测;用电导率仪测量瓷器脱盐过程中电导率变化情况。结果表明,出水瓷器表面凝结物,容易机械去除的样品,其成分主要是镁方解石及文石;不容易机械去除的样品,其成分主要是锰白云石及文石。瓷器微孔内的白色物质为含氯盐分。经两周时间的脱盐清洗,出水瓷器的脱盐电导率值降至较低水平。本工作结果可为西沙海域出水瓷器的后续保护提供资料。     

几件明代斗彩和清代粉彩瓷片的科学分析

为探索光谱学和光学技术组合对中国彩瓷的无损综合科学分析,科学揭示我国两种著名彩瓷斗彩和粉彩的宏观和微观特征,探讨其制作工艺,应用多光谱成像、超景深体视显微分析、光学相干层析(OCT)成像、能量色散型X射线荧光分析和激光拉曼光谱技术,对4件景德镇官窑烧制的明代斗彩瓷片和2件山西新绛县绛州州署衙遗址出土的清代粉彩瓷片,进行了面、点相结合的综合分析。分析结果表明:这两类彩瓷的釉上彩与白釉域的化学成分有明显区别,明代斗彩的釉上彩中含有较高的铅元素,而清代粉彩的釉上彩中同时含有铅和砷。明代斗彩的深红色釉上彩为赤铁矿着色,而清代彩瓷片的红色釉上彩为赤铁矿着色,深红色釉上彩为朱砂着色;明代斗彩的绿彩为铜离子着色,青花呈色元素是钴。采用多光谱成像技术识别和分析了釉上彩区域一些隐藏的图像信息,同时也通过OCT成像技术直观分析了釉上彩区域的断面结构。研究为早期釉上彩瓷器制作工艺的认知提供了科学依据,也为今后的科学研究提供了有益的方法学参考。对这两种各具特色的彩瓷进行科学分析对认识中国古代陶瓷技术的发展具有重要意义。     

大理旅游区开发建设的地理评价

旅游开发的地理评价是旅游地理学研究的重要内容。对旅游区开发建设的地理学评价,应从人地关系的角度,分析旅游业的发展对区域的社会、经济和环境的影响,同时探究区域背景中对旅游业发展的促进和制滞作用。即采用部门--区域交叉相关分析的方法。本文选取了涉及大理市社会、经济、环境的35个要素,根据1984~1988年间的情况,在定量演算的基础上展开定性分析,评价了旅游业对大理市的社会、经济和环境的影响方面程度,亦找出了大理市区域背景中影响旅游业发展的主导方面和不够协调的方面。为进一步制定与大理市社会进步、经济发展、环境保护相协调的大理旅游区开发建设规划提供了思路和佐证。     

零售商业空间组织的市场分析

本文从市场地理学的角度上,对零售空间组织的决策过程--市场分析过程进行了研究。指出该过程应包括区域社会经济分析,即提供发展背景;贸易区分析,即确定区位发展可行性;消费者研究,即确定组织经营形式。     

西部少数民族地区科技创新中的科研机构改革

该文分析了西部少数民族地区当前科研机构改革的进展及存在的问题,提出了加快科研机构改革步伐,促进科技创新的对策建议。     

New light on old pumice: the origins of Mediterranean volcanic material from ancient Egypt

This paper presents and discusses the Neutron Activation Analysis (NAA) results newly obtained from pumice pieces found decades ago at the Egyptian sites of Maiyana, Sedment, Kahun, and Amarna – now in the collections of the Ashmolean Museum, Oxford, and the Petrie Museum of Egyptian Archaeology, London – which could be successfully related to several volcanic eruptions in the Mediterranean. The work contributes to the constant accumulation of knowledge concerning the first appearance of pumice from the so-called Minoan eruption of the Santorini volcano. In addition, it unexpectedly sheds more light on the long-distance trade of Mediterranean volcanic material in the Bronze Age world by disclosing another connection between Lipari and the Eastern Mediterranean.     

Analysis of Carbon Fiber Sheet-Retrofitted RC Bridge Columns Under Lateral Cyclic Loading

In recent years, the use of carbon fiber sheet (CFS) to provide lateral confinement for enhanced ductility and strength of reinforced concrete bridge columns has been increasing. While the monotonic behavior of CFS-confined concrete has been studied extensively, its cyclic response has not been fully understood. Most of the available studies are experimental investigations, hence there is a need to develop an analytical model to simulate the experimental results. Analysis of the hysteretic behavior of CFS-retrofitted circular columns is presented in this article using the fiber element that is based on cyclic constitutive models of longitudinal reinforcement and concrete confined by both CFS and tie reinforcement. The analysis was verified based on available cyclic test data and the analysis provides good agreement with the experimental results. Results show that flexural strength and ductility of columns wrapped with CFS increases as CFS ratio increases. However, as tie reinforcement ratio increases, there is no much difference on the hysteretic response for low tie reinforcement ratios. Using the fiber element analysis, the effect of CFS retrofit on the seismic response of a 7.5 m tall prototype pier built in the 1970s to 1980s is also clarified.     

Seismic Analysis of Masonry Gravity Dams Using the Discrete Element Method: Implementation and Application

Much research in recent years has focused on the seismic analysis of concrete and earthfill dams, and few works have addressed the case of masonry dams. The structural behavior of masonry dams is controlled essentially by its discontinuous nature, which may induce significant nonlinear response during an intense earthquake. In this article, a numerical tool based on the Discrete Element Method is presented, aimed at the static, dynamic, and hydromechanical analysis of masonry gravity dams. The use of discontinuous models is mandatory for the study of failure mechanisms involving the masonry discontinuities, the dam-rock interface or the rock mass joints. The Discrete Element Method is able to assemble continuous and discontinuous meshes simultaneously in the same model, providing a versatile tool to consider various assumptions and levels of analysis, ranging from simplified to detailed structural representations. A comprehensive study of the seismic behavior of Lagoa Comprida Dam, located in Portugal, is presented. Both continuous and discontinuous models were developed to assess the main failure mechanisms, including overstress, partial and global sliding, and overturning.     

Considering Soil-Nonlinearity Effect on Seismic Performance Evaluation of Structures based on Pushover Analysis

According to the most of current seismic codes, nonlinear soil behavior is commonly ignored in seismic evaluation procedure of the structures. To contribute on this matter, a pushover analysis method incorporating the probabilistic seismic hazard analysis (PSHA) is proposed to evaluate the effect of nonlinear soil response on seismic performance of a structure. The PSHA outcomes considering soil nonlinearity effect is involved in the analysis procedures by modifying the site-specific response spectrum. Results showed that incorporation of nonlinear soil behavior leads to an increase in displacement demand of structures which should accurately be considered in seismic design/assessment procedure. Results of implemented procedure are confirmed with the estimated displacement demand including soil-structure interaction (SSI).     

新疆与历代中原王朝政治关系的计量分析

自西汉在新疆设官以来的两千多年中,新疆和中原王朝保持着四类政治关系。本文首先简述了中原王朝在新疆设置政权的沿革,然后以计量史学的方法对四类政治关系存续的时段分别予以统计,以关系的数量程度说明关系的性质。统计结果显示,新疆地区全部或部分在两千多年的大部分时段中处于中原王朝辖治之下,从而表明新疆自汉代以来就是中国领土的一部分。