毕仲衍《中书备对》目录的发现及其意义

北宋毕仲衍所修的《中书备对》今已散佚,传世的一些文献尚存其中少数内容。《四库全书》文津阁本《西台集》中收有一篇题名为《毕仲衍〈上编次官制卷目稿札子〉》的奏议。据考证,它是毕仲衍进呈《中书备对》时所上的奏议,与元丰新官制无关。其中的“卷目”,正是《中书备对》的目录。这个目录的发现,对考证此书的卷数、了解该书的内容和辑佚这部残存文献有重要价值。     

SHAKING TABLE DYNAMICS: RESULTS FROM A TEST-ANALYSIS COMPARISON STUDY

This paper presents the results of a comprehensive comparison study between the analytically predicted and experimentally identified dynamics of the shaking table system built recently in the Structural Engineering Laboratory at Rice University in Houston, Texas. The primary objectives of the research presented here are two-fold: (1) to shed light into the dynamic performance of asmall-tc-medium size, uni-axial, servo-hydraulic, displacement-controlled shaking table system, and (2) to validate a linearised dynamic model of the system (in the form of the total shaking table transfer function) developed earlier by the authors from basic principles. The analytical model incorporates the inherent dynamic characteristics of the various components of the shaking table system (i.e. controller, servovalve, actuator, test specimen, and reaction mass) and their dynamic interaction.

The test-analysis correlation study performed over a wide range of operating and payload conditions provides useful information on the sensitivity of the shaking table transfer function to control gain parameters and how it can be used to tune the shaking table controller for optimum performance under various payload conditions. The good test-analysis correlation results obtained validate the analytical shaking table model, show its robustness, and provide keen insight into the underlying coupled dynamics of a shaking table system. In order to achieve this good test-analysis correlation, it was crucial to include a time delay in the analytical model of the shaking table system (innovative feature of the model to account for the time lag in the response of the servovalve-actuator system). The expected significant dynamic interaction between payload and shaking table is also confirmed by this study.     

A Study on Black‐Body Celadon Excavated in The Altar Guan and Literature Ge (Longquan Ge) Kilns by EDXRF

Samples of celadon were collected from the Altar Guan Kiln in Hangzhou, and from the Xiaomeizhen and Xikou Kilns, two subordinate kilns of the Longquan Kiln producing black‐body celadon called Literature Ge. Both the elemental contents in the sample bodies and the glaze were measured. The results reveal that the sample bodies contain fingerprint information for provenance, while this was lost in the glaze during the production process. The TiO₂, MnO and Rb₂O contained in the bodies are fingerprints to distinguish between celadons from the Xiaomeizhen and Xikou Kilns. In the Altar Guan Kiln, some low‐TiO₂ samples were found and their body colour is much lighter than some others, but they do not differ with regard to iron content. This indicates that both titanium and iron are indispensable for the blackness of the bodies: they may react to form some black minerals during the firing process. Ultimately, samples from the Literature Ge and Altar Guan Kilns differ in their body constituents. Principal component analysis reveals that the samples can be divided into two groups, corresponding to the two different areas.     

Partitioning chi-square for the analysis of frequency table data: an archaeological application

Archaeologists often wish to compare observed frequency distributions with expectations generated by a model. We describe a technique of partitioning chisquare which yields information about goodness of fit to a model and about homogeneity among populations simultaneously, and which is often superior to other commonly used methods of evaluating frequency data. The technique is demonstrated with data from the Upper Paleolithic rockshelter Le Flageolet I. The results suggest selective raw material use by the Aurignacian occupants.     

传统方法加固馆藏浮放文物抗震性能试验

为探索馆藏浮放文物的有效抗震加固方法,采用振动台试验手段,研究了传统方法加固浮放文物的抗震性能。基于故宫博物院某展柜原型尺寸,制作了1:1比例陈列柜模型。在陈列柜内浮放一轻质陶瓷文物,分别考虑采用砂子、塑料卡、鱼线、橡皮泥及磁铁加固文物,进行了振动台试验。通过白噪声激励,获得了陈列柜基频分布;通过输入不同强度、不同类型的地震波,获得了不同方法加固条件下陈列柜和文物的位移响应、加速度响应和和动力放大系数,评价了不同方法的加固效果。结果表明:陈列柜的基频与输入地震波相差较大,这是陈列柜震害不明显的主要原因之一;传统方法加固文物后,输入地震波的加速度仍有一定放大,但是与加固前文物相比,文物的位移和加速度响应均有所减小,且文物因摇晃幅度而产生倾覆的可能性减小。此外,从减小文物加速度响应峰值角度考虑,橡皮泥和鱼线加固文物效果优于其它方法。试验结果可为文物防震保护研究提供较全面的参考。     

明初南京天坛分合祀的变迁

明初朱元璋对国之大事的社稷行礼制式,经历了由南北对峙的天、地坛分祀制到合天地为一坛的合祀制,其分、合坛的建筑布局亦各不相同。     

单檐歇山式古建筑抗震性能振动台试验

为有效保护古建筑,采用振动台试验方法,研究了中国明清官式木构古建的抗震性能。以故宫某单檐歇山木构古建为对象,制作了1∶2缩尺比例模型。模型含浮放柱底、柱架、斗拱、歇山屋顶、墙体等所有构造,且施工工艺完全符合中国明清官式木构古建施工规定。通过施加白噪声激励,获得了模型的基频和阻尼比。通过施加不同强度等级的1940年El-Centro波,获得了模型典型节点的位移和加速度响应,讨论了模型的减震系数,评价了浮放柱底、榫卯节点、斗拱、屋顶、墙体等构造的抗震性能。结果表明:模型的振动形式表现为平面内的扭摆,其原因与歇山式屋顶质量分布不均密切相关。模型的震前基频为1.47Hz,阻尼比为4.6%。地震作用下,模型的位移及加速度响应曲线近似稳定、均匀。尽管屋顶构造则对地震力有一定放大作用,但浮放柱底、榫卯节点、斗拱等构造能发挥较好的耗能减震作用。对于不同构造而言,榫卯节点的减震性能最好,其减震系数可降至0.30;斗拱次之,其减震系数可降至0.53;而浮放柱底与柱顶石之间的摩擦耗能性能最弱,其减震系数最小值为0.66。墙体在地震波强度增大过程中发生倒塌,但不影响结构整体稳定性。因此,单檐歇山式木构古建具有良好的抗震性能。     

Simulation of Shake Table Tests on Out-of-Plane Masonry Buildings. Part (VI): Discrete Element Approach

ABSTRACT

Although many experimental tests and numerical models are available in the literature, the numerical simulation of the seismic response of existing masonry buildings is still a challenging problem. While the nonlinear behavior of masonry structures is reasonably predictable when the out-of-plane behavior can be considered inhibited, when the in-plane and out-of-plane responses coexist and interact, simplified models seem unable to provide reliable numerical predictions. In this article, taking advantage of the experimental tests carried out in a shaking table on two masonry prototypes at LNEC, a macro-element approach is applied for the numerical simulations of their nonlinear response. The adopted approach allows simulating the nonlinear behavior of masonry structures considering the in-plane and out-of-plane responses. Since it is based on a simple mechanical scheme, explicitly oriented to representing the main failure mechanisms of masonry, its computational cost is greatly reduced with respect to rigorous solutions, namely nonlinear FEM approaches. Two modeling strategies are adopted, namely a regular mesh independent from the real texture of the prototypes and a detailed one coherent with the units disposal. The numerical results are discussed and the correlation between the nonlinear static analyses and the dynamic response is provided.     

Pottery Production in the Buddhist Communities in Central Asia: The Kushan‐Sassanian Pottery Workshop of Kara Tepe (Termez,Uzbekistan)

We present the first full archaeometrical study of Kushan‐Sassanian pottery from the Buddhist monastic complexes at Kara Tepe (Termez, Uzbekistan), recovered both in the pottery workshop and in the monastery, using a combination of analytical methods (XRF, XRD, SEM–EDS and OM). The study allowed the identification of the reference group, the correspondent fabric, the raw materials used for its productions, some of the technological processes involved in manufacture and several weathering processes. All the results confirm that the kiln was supplying the religious community of the monastery with pottery, made using local raw materials, and highlight the possibility that the kiln could have supplied the nearby monastic complexes, where no kilns have been found. Further archaeological evidence indicates the existence of specialized potters working itinerantly at the broader Bactrian area.