The Numerical Study of Base-Isolated Buildings Under Near-Field and Far-Field Earthquakes

The behavior of base-isolated building frame is investigated with the help of a numerical study for far-field and near-field earthquakes with directivity and fling-step effects. Both design-level and extreme-level earthquakes are considered. Selected response parameters are peak floor displacement, acceleration, base shear, and isolator displacement. Inelastic behavior of base-isolated structure during the earthquake is investigated performing nonlinear time history analysis of a ten-story building frame. This study shows that base isolation is not effective for near-field earthquakes. Even for design-level earthquake, the frame gets significantly into inelastic range for earthquakes with fling-step effect.     

Seismic Damage Reduction of a Structural System based on Nontraditional Sliding Interfaces with Graphite Lubrication

In this paper, we propose a free-standing structure that is unanchored to its foundation and has a cost-efficient interface consisting of common construction materials (steel, mortar, and iron) with graphite lubrication; this structure is expected to behave as an earthquake-resistant structure during small earthquakes and a base-isolated structure during large earthquakes. To realize the structure, this study examined the frictions of the interfaces in shaking table tests. In addition, the seismic responses of the free-standing structures based on the interfaces were examined via incremental dynamic analyses with 44 ground motions and a simple model of typical Japanese steel structures.     

多种科技方法在古月桥勘察修缮设计中的应用

建于南宋嘉定六年(公元1213年),位于浙江省义乌市的古月桥是折边拱桥这种桥梁发展过渡形式中不可多见的典型实证,具有极高的历史、科学、艺术、文化和社会价值。为了明确古月桥目前的状态,分析其主要威胁及病害原因,判断结构稳定性,进而制定有针对性的修缮方案,采用多种科技方法对古月桥进行了勘察和综合判断。面对桥身残破的现状,工作组采取了三维激光扫描、微观实验、结构分析等多种科技方法综合勘察,不仅较为清晰的地了解了古月桥的病害威胁,也分析了其背后致因及相互之间的联系;最终对古月桥稳定性及保存状况做出了综合判断。上述多种方法的应用,不仅相互印证了勘察结论,也为后续保护工作提供了重要的依据。     

Transitions in cast iron technology of the nomads in Mongolia

Metallurgical study of seven cast iron artifacts recovered from sites of the former Xiongnu (BC 3rd to AD 1st), Turk (AD 6th to 8th), Khitan (AD 10th to 12th), and Mongolian empires (AD 12th to 15th) shows that the earlier Xiongnu and Turk artifacts were made of cast iron alloys of near eutectic composition. The later Khitan and Mongol objects had greatly reduced carbon content in the range of ultrahigh carbon steel rather than cast iron, and contained more than 0.5 mass % silicon as an alloying element. Inclusions high in sulfur, phosphorus or silicon are also present. These differences suggest that Mongolia experienced a technical transition a few centuries before the establishment of the Mongolian empire, which is in agreement with some written accounts. The microstructures of the cast iron artifacts are compared with the related archaeological and documentary evidence. The results suggest that the use of fossil coal in smelting and the state policy of controlling iron production were the major factors responsible for the transition.     

The Origin and Archaeometallurgy of a Mixed Sulphide Ore for Copper Production on the Island of Kea,Aegean Sea,Greece

At the hill of Agios Symeon, on the island of Kea, Aegean Sea, Greece, ancient metallurgical slags with a high Pb–Zn–Cu content have been found. Thermodynamic simulations have been carried out, using the FactSage? thermodynamic database computing system, with a view to understanding the ancient metallurgical processes that produced the observed slag compositions and morphologies. The simulations demonstrate that the slag samples resulted from Cu‐making processes. It would thus appear that mixed ores were used, containing Cu₂S–FeS–PbS with significant amounts of sphalerite (ZnS) as impurity. The roasted ores were reduced at relatively high oxygen potentials at ～1125°C to form Cu containing low levels of Pb, Fe and Zn.     

Development of Collaborative Structure Analysis (CSA) System and Its Application to Investigate Effects of Soil-Structure Interaction

In this article, a collaborative structure analysis (CSA) system is developed for integrating different finite-element simulation programs. In this system, a simulated structure is divided into multiple substructures, and the interaction between the substructures is considered. Interfaces for the commercial finite-element program ABAQUS and for an open-source framework for structure analysis, OpenSees, are developed to achieve CSA integration. The CSA system is applied to analysis of a soil-structure interaction (SSI) problem, and the effects of SSI are investigated, and the efficiency and accuracy of the system are demonstrated.     

中国古文献中所看到的古代建筑结构力学认识研究

考察古代人的结构力学认识,是对古建筑结构的分析及解释必不可少的研究之一。因为与现代建筑结构不同,古代建筑结构主要取决于当时工匠们的经验与直观判断。古代人对结构力学的认识概念,我们从中国古文献中可以看到。通过本研究发现,古代人已经有对力与荷重的力学认识以及古建筑的对称结构就是从古代力学的平衡概念出发而发展的。     

清代早期四合如意云寸蟒纹织金妆花缎的结构分析与保护修复

受北京艺术博物馆的委托,对两件香色地四合如意云寸蟒纹织金妆花缎进行保护修复。两件妆花织物质地柔软、组织结构紧凑、纹样细腻、设色庄重。但经长期自然和人为因素的影响,织物多处破损、开裂、脱丝、破洞、污渍等,圆金和片金纹纬上的金片大量脱落,整体污染较为严重,质地脆弱,无法研究和展出。本文通过研究妆花所承载的历史文化信息、综合织物的质地、组织结构、纹样形态、设色特征等诸多因素,将其定为清早期织物。应用三维视频显微镜和电子丝绸尺软件对织物组织结构、破损程度进行了分析。在此基础上,制定了保护修复工作目标和方案。修复后的两件织物基本恢复了原貌,效果较好,可以作为研究中国丝织品的实物根据。     

从成吉思汗经略西北边疆的成败看文化力的作用——纪念成吉思汗登大汗位800周年

本文概括论述了成吉思汗经略西北边疆的出众文略,指出他组建新的依靠力量,经略中西驿路交通,短短几年便统一中国西北边疆,达到了建立欧亚帝国和促进人类古代最广大的一次“握手”的一代辉煌,以及成吉思汗处理西北民族关系和塑建开放性民族结构之成功。同时剖析了他因文化的局限性而造成的两大失误给他本人和子孙带来的悲剧。最后,剖析了领土观念、制度文化、利益依附关系如何成为边疆分裂的根本因素。     

旅游客源市场结构分析——以南京市为例

文章首先综述了旅游客源市场结构的有关理论,指出了研究旅游客源市场结构的重要意义,接着,作者以南京市为例,在大量数据资料的基础上,对南京市客源市场空间结构、时间结构及旅游类型结构进行了分析,并就如何开拓南京市旅游客源市场进行了探讨。