SEISMIC AMPLIFICATION AT A SOFT SOIL SITE WITH LIQUEFIABLE LAYER

It is well known that local soil conditions play a key role in the amplification of earthquake waves. In particular, a liquefiable shallow soil layer may produce a significant influence on ground motion during strong earthquakes. In this paper, the response of a liquefiable site during the 1995 Kobe earthquake is studied using vertical array records, with particular attention on the effects of nonlinear soil behaviour and liquefaction on the ground motion. Variations of the characteristics of the recorded ground motions are analysed using the spectral ratio technique, and the nonlinearity occurring in the shallow liquefied layer during earthquake is identified. A fully coupled, inelastic finite element analysis of the response of the array site is performed. The calculated stress-strain histories of soils and excess pore water pressures at different depths are presented, and their relations to the characteristics of the ground motions are addressed.     

ATTENUATION RELATION FOR WEST EURASIA DETERMINED WITH RECENT NEAR-FAULT RECORDS FROM CALIFORNIA,JAPAN AND TURKEY

Strong ground motion close to a fault can be expected to be very large, so its estimation is essential for human safetv. Although a few strong-motion data exist for the west Eurasian region, we proposed in a previous work [Berge-Thierry et al., 2003] an attenuation relation for spectral acceleration using strong-motion data recorded in west Eurasia (mainly in Europe) and some in the western United States: this relationship was derived for the French Safety Rule, which is applied for seismic hazard assessment at nuclear power plants. In this study, we propose a constraining of the amplitude saturation term related to the proximity of the fault, and an adding of an amplitude saturation term in the regression model. We add, to the data-set previously used to derive the west Eurasian attenuation relationship strong-motions recorded during recent large earth-quakes: the 1995 Hyogo-ken Nanbu (Kobe) event in Japan and the 1999 Kocaeli (Izmit) event in Turkey. The regression analysis, adopted from Fukushima and Tanaka [1990], is non-linear, so an iterative procedure is applied. The determined regression coefficients lead to a prediction of a peak ground acceleration of about 0.7 g for soil site conditions at a fault distance of 0.5 km. The Q coefficient deduced, from the distance coefficient is in agreement with scattering Q models. The introduction of the saturation term leads to significantly lower predictions of average spectral accelerations at short distances as compared with using the Berge-Thierry et al. [2003] empirical model.     

INTEGRATED PASSIVE-ACTIVE SYSTEM FOR SEISMIC PROTECTION OF A CABLE-STAYED BRIDGE

This paper presents an integrated passive-active (i.e. hybrid) system for seismic response control of a cable-stayed bridge. Since multiple control devices are operating, a hybrid control system could alleviate some of the restrictions and limitations that exist when each system is acting alone. Lead rubber bearings are used as passive control devices to reduce the earthquake-induced forces in the bridge and hydraulic actuators are used as active control devices to further reduce the bridge responses, especially deck displacements. In the proposed hybrid control system, a linear quadratic Gaussian control algorithm is adopted as a primary controller. In addition, a secondary bang-bang type (i.e. on-off type) controller according to the responses of lead rubber bearings is considered to increase the controller robustness. Numerical simulation results show that control performances of the integrated passive-active control system are superior to those of the passive control system and are slightly better than those of the fully active control system. Furthermore, it is verified that the hybrid control system with a bang-bang type controller is more robust for stiffness perturbation than the active controller with a μ-synthesis method, and there are no signs of instability in the over-all system whereas the active control system with linear quadratic Gaussian algorithm shows instabilities in the perturbed system. Therefore, the proposed hybrid protective system could effectively be used for seismically excited cable-stayed bridges.     

ANALYTICAL MODELS FOR BRICK MASONRY INFILLED R/C FRAMES UNDER LATERAL LOADING

Proposed in this paper are two analytical models for predicting the inelastic response of unreinforced brick masonry infills in reinforced concrete frames subjected to mono-tonic and reversed cyclic loading. The first model is based on the traditional diagonal strut concept, while the second one is a simple isoparametric element with shear deformation only. All the essential characteristics of the hysteretic behaviour of the panel, including strength and stiffness degradation, pinching and slippage, are explicitly taken into account. The models are implemented in a general-purpose program for the inelastic time-history analysis of structures, and are used for studying the seismic behaviour of typical multistorey frames with various arrangements of infill panels, including structures with an open ground storey. The results of the analysis are in agreement with both experimentally observed behaviour and with experience regarding seismically damaged buildings.     

Latitudinal variation in a photoperiod response gene in European barley: insight into the dynamics of agricultural spread from ‘historic’ specimens

Between ca. 6000 BC and ca. 500 BC, barley cultivation spread across the continent of Europe from the extreme south to the extreme north. Carbon-dating would suggest that this spread, and indeed the spread of crop cultivation generally, varied in its pace, with ‘delays’ at certain points along its route. Such delays in the spread of agriculture have been explained as resulting from the slow assimilation of agricultural practices by existing indigenous human populations or as the time taken for the crops to adapt to novel climatic conditions, such as altered temperature regimes and day-lengths. A mutant form of the photoperiod response gene, Ppd-H1, causes barley to be non-responsive to long days, while the wild-type responsive form allows plants to flower in response to long days. We sequenced this gene in 65 ‘historic’ barley accessions, from the late 19th and early 20th centuries, in order to explore the potential role of environmental adaptation in the spread of agriculture. We chose to use ‘historic’ material, to complement the richer patterns in extant genetic lines, by spreading the data range in both time and space. Our ‘historic’ barley data shows a latitudinal divide in the Ppd-H1 gene similar to that found in extant lines, but with clearer geographical resolution, and extending northwards into the Arctic Circle. We discuss the implications of our results in relation to the dynamics of agricultural spread across Europe.     

辜鸿铭对"黄祸"论的回应

19世纪末20世纪初,西方把中国人妖魔化的“黄祸”论甚嚣尘上。对此,在政治上和文化上都属保守主义者的辜鸿铭,用外文撰写了一系列文章加以批驳。辜文主要从中西文化的不同性格入手,论证中国文明是高度发达的文明,中国人是深具“理性意识和道义感”的民族,并以具体事例证明一些在华西方人的言行不符合文明人的标准。他还指出各自“扩展”,即实现“知识和道德意义上”的“门户开放”,是消除双方恐惧和敌意的根本办法。     

中关村科技园区创意基地型园区发展研究

中关村科技园区以德胜园、雍和园、石景山园为代表,规划建设创意基地型园区,这对北京市加快文化创意产业发展、积极参与国际创意产业分工等具有重要意义。本文在分析创意基地型园区的基本情况并借鉴国际经验的基础上,指出中关村科技园区创意基地型园区存在的主要问题,并探讨了促进其发展的对策。本文认为中关村科技园区创意基地型园区的发展应侧重于四个方面:为园区提供"新生"的产业发展空间、供给适应创意产业发展需要的特殊基础结构、构造创意产业集群并形成完整的产业链、注重园区之间错位发展。     

建国初期湖北没收官僚资本的措施及成效

解放前,湖北官僚资本企业遍及电力、化工、纺织、机械、炼油、印刷、军工、公用等工业各行业,主宰湖北经济命脉。从湖北解放至1952年,湖北军管会采取种种举措,彻底没收了在鄂的全部官僚资本,并建立了社会主义国家银行、国营工商业等国营经济,奠定了湖北的社会主义经济基础。     

日本的不良债权及其政策措施

自泡沫经济崩溃后产生不良债权以来,日本金融机构的不良债权就一直是持续增加的趋势,这在90年代后期尤为明显,巨额的不良债权对金融机构和日本经济都产生了极为严重的影响,为此,日本政府通过制订有关金融法规推进金融改革,实和金融稳定和政策和金融缓和政策,加强金融监督和金融检查等有关措施,千方百计地解决不良债权问题,日本政府解决不良债权的政策措施并未能阻止不良债权的继续增加,其处理不良债权的计划一再的落空,今后也不会一帆风顺,尽管如此,有关政策措施确实是起到了一定的作用,有值得学习和借鉴之处。     

科技手段与书画鉴定

在当今的器物学鉴定工作中,不少高科技的鉴定技术已经成功地应用于文物年代的分期断代和真伪鉴别上。但在古代书画鉴定工作中,由于其特殊性和复杂性,目前仍停留在传统的鉴定方法上。本文就运用一些必要的科学手段来证实鉴定结果进行了深入的探讨