实验室微型发掘方法在北周武帝孝陵 发掘中的应用

1994年经国家文物局批准,陕西省考古研究所对北周武帝孝陵进行了抢救性发掘,由于墓葬多次被盗,又多次进水,导致墓内的文物发生严重扰乱和腐蚀,尤其是墓内发现的大量易碎、细小及糟朽的有机质文物,使现场清理遇到了很大的困难。为了最大程度地获取地层中的所有考古信息,首次大规模、针对性地对孝陵五号天井东、西龛,四号天井东龛,甬道及墓室的文物采取了整体分割打包,运回实验室进行微型发掘的方法。通过对现场提取的74个石膏包的微型发掘和清理,获得了在现场无法发现的重要文物和遗迹,共清出文物2330件。尤其是直径不足1mm的无色琉璃珠在显微镜下的发现更是将微型发掘的优势凸显到了极点。它不仅弥补了现场发掘的不足,更是利用先进仪器,将考古发掘、科技考古和文物保护完美地进行了融合。实践证明实验室微型发掘方法是考古现场发掘不可或缺的必要手段。     

中国星级酒店相对效率集聚的空间分析及提升策略

选取大陆31个省级区域2000-2009年的面板数据,基于改进的DEA模型,对省际星级酒店的相对效率进行测算,进一步对相对效率的空间集聚态势及影响机理进行分析。大陆星级酒店相对效率的变动主要受规模效率驱动,大部分省份星级酒店的规模效率处于递减状态,这种粗放型的增长方式从长远角度看,不利于星级酒店业的健康良性发展。中国星级酒店相对效率及其空间集聚态势都表现出与经济发展水平负相关的态势,各项效率的影响机理不同。最后基于波士顿矩阵分析法,对提高星级酒店相对效率提出相应的策略。     

Integration of use-wear with protein residue analysis – a study of tool use and function in the south Scandinavian Early Neolithic

This study presents research on how an integration of use-wear analysis with protein residue analysis can produce new results on prehistoric tool use and function. Thirty flint artefacts from an Early Neolithic TRB site in south Sweden were analysed for both use-wear and protein residues. The results show a positive correlation between the two methods. The Early Neolithic tools analysed were primarily used to process fish.     

Applying the H/V Method to Dense Cities. A Case Study of Valencia City

The aim of this study was to apply Nakamura's technique to Valencia city center, after some preliminary tests in Barcelona. Previous studies of Barcelona had measured periods in restrictive conditions and in various types of material ranging from very soft soil (with a predominant period of approximately 2 s) to rock (0.3 s), and under different measurement conditions. The Valencia city center measurements were taken by using the distance from buildings and car and pedestrian traffic to construct a measurement grid that was as regular as possible. We also estimated possible soil-structure interaction to detect potential vulnerability.     

A Modified Capacity Spectrum Method with Direct Calculation of Seismic Intensity of Points on Capacity Curve

A direct methodology for solving the seismic intensity of each point on the capacity curve is proposed. By utilizing the procedure, a continuous curve between the structural response and the seismic intensity, the structural response function, can be easily generated. Unlike previous procedures that search for the performance point of a determined seismic intensity, the proposed methodology easily draws the full curve without iterations. The procedure is applicable to both a smooth design spectrum and an actual response spectrum. Examples indicate the methodology is accurate and fast, and convenient to be combined with existing procedures, such as Modal Pushover Analysis.     

An Analytical Study on the Seismic Vulnerability of Masonry Buildings in India

Two analytical models for unreinforced masonry (URM) buildings are proposed with the aim to simulate their seismic response and to estimate corresponding vulnerability functions. The proposed models are implemented in SAP 2000 nonlinear software to obtain capacity curve parameters for representative Indian URM buildings, based on a field survey and statistical analysis. Vulnerability functions are estimated using the obtained capacity curves. Damage Probability Matrices (DPMs) are obtained using the approximate PGA-intensity correlation relationship as per Indian seismic building code and are compared with the commonly used intensity scales and empirical damage data observed after the 2001 Bhuj earthquake.     

Study on a Simplified Calculation Method for Hydrodynamic Pressure to Slender Structures Under Earthquakes

Based on Morison hydrodynamic force theory, a simplified calculation method for hydrodynamic force to slender structures is proposed. A typical cylindrical deep water pile was chosen for study and the simplified method was used to analyze the influence of hydrodynamic pressure on the pile. Then the finite element method was used to study the dynamic characteristics of the model, and the results from both methods were compared. A comparison was also made between the shaking table test on the south tower of the Nanjing Yangtze 3rd River Bridge and the results from the simplified method.     

Dynamic Interaction between Rigid Foundations on Multi-layered Stratum

This article concerns the cross-interaction problem among multi-foundations on a linearly viscoelastic medium at very small shear strains. In the analysis, the foundations are discretized into a number of sub square-elements. The dynamic response within each sub-element is described by the Green’s function, which is obtained by the Fourier-Bessel transform and the precise integration method. Incorporating the displacement boundary condition and the force equilibrium of the foundations, it obtains the dynamic impedance and compliance functions of the foundations. Extensive results for two rigid circular foundations placed at different separations are presented. Parametric studies are carried out on the dynamic interaction among adjacent foundations. Illustrative results for several closely spaced foundations are also illustrated.     

Study on Low-Frequency Characterizations of Pulse-Type Ground Motions through Multi-Resolution Analysis

This article makes an attempt to investigate the low-frequency characterizations of pulse-type ground motions through ground motion components instead of original records. A decomposed method based on multi-resolution analysis is introduced in this article. The accuracy and validity of the method is tested in frequency domain, time domain and dynamic response. A dataset of 398 low-frequency components is obtained after the decomposition of 91 typical pulse-type records. A probabilistic model to describe the proportion of low-frequency components in corresponding original ground motions is established. At last, the decomposed method is used to investigate the impulsive characterizations of pulse-type ground motions.     

Elastic Displacement Spectrum-Based Design Approach for Buckling-Restrained Braced Frames

The design focus for a buckling-restrained braced frame (BRBF) is that the buckling-restrained braces (BRBs) dissipate most of the seismic energy while the main frame retains a degree of elastic stiffness under a major earthquake. An elastic displacement spectrum based design method is presented in this article, which can directly determine the sectional area of the BRBs. The yield displacement in the roof of the main frame is taken as the target displacement under a major earthquake. An elastic displacement design spectrum is used to solve the target period of the BRBF. To validate this method, a six-story buckling-restrained braced steel frame is designed using the proposed method, and a series of nonlinear response history analyses (RHAs) are performed to verify the design result. The example shows that the required BRB area can be simply and accurately determined by the proposed method. The error between the given target displacement and the RHA results is 4.0% and 21.3% for BRBFs designed with BRB yield strength of 235 Mpa and 100 Mpa, respectively.