Selection of earthquake ground motion records: A state-of-the-art review from a structural engineering perspective     

Evangelos I. Katsanos  Anastasios G. SextosGeorge D. Manolis 《Soil Dynamics and Earthquake Engineering》2010

This paper reviews alternative selection procedures based on established methods for incorporating strong ground motion records within the framework of seismic design of structures. Given the fact that time history signals recorded at a given site constitute a random process which is practically impossible to reproduce, considerable effort has been expended in recent years on processing actual records so as to become ‘representative’ of future input histories to existing as well as planned construction in earthquake-prone regions. Moreover, considerable effort has been expended to ensure that dispersion in the structural response due to usage of different earthquake records is minimized. Along these lines, the aim of this paper is to present the most recent methods developed for selecting an ‘appropriate’ set of records that can be used for dynamic analysis of structural systems in the context of performance-based design. A comparative evaluation of the various alternatives available indicates that the current seismic code framework is rather simplified compared to what has actually been observed, thus highlighting both the uncertainties and challenges related to the selection of earthquake records.  相似文献   

Biochemical and microbial features of shallow marine sediments along the Terra Nova Bay (Ross Sea,Antarctica)   总被引：1，自引：0，他引：1  

Franco Baldi  Davide Marchetto  Francesco Pini  Renato Fani  Luigi Michaud  Angelina Lo Giudice  Daniela Berto  Michele Giani 《Continental Shelf Research》2010

Shallow marine sediments were collected from seven stations (three of which located at Gerlache Inlet, two at Tethys Bay, one at Adelie Cove and one just beneath the Italian Research Base) along the Terra Nova Bay coast (Ross Sea, Antarctica). Their chemical, biochemical and microbiological properties were studied in order to provide further insights in the knowledge of this Antarctic benthic ecosystem. Overall, the organic carbon (OC) represented the major fraction of total carbon (TC) and displayed concentrations similar to or slightly lower than those previously measured in Antarctic bottom sediments. The biopolymeric carbon within OC ranged from 4.1% to 19.9% and showed a wide trophic range (65–834 μg g⁻¹ d.w.). Proteins (PRT) represented on average the main biochemical class contributing to labile organic carbon, followed by lipids (LIP) and carbohydrates (CHO). The activity of aminopeptidase, β-d-glucosidase, alkaline phosphatase and esterase was checked, giving the highest values at Tethys Bay and at the deepest water sediments. The principal component analysis, which was computed considering physical, chemical (elemental and biochemical sedimentary composition) and microbiological parameters (including bacterial abundance, ectoenzymatic activities, T-RFs richness and diversity indices), allowed to obtain two main clusters (“Tethys Bay” and “other stations”). Based on data obtained, two representative 16S rRNA clone libraries using samples from Tethys Bay and Gerlache Inlet were constructed. The sequences of 171 clones were compared to those available in public databases to determine their approximate phylogenetic affiliations. Both aerobic and anaerobic bacteria were disclosed, with the majority of them affiliated with the Gamma- and Deltaproteobacteria, Bacteroidetes and Acidobacteria. The occurrence of strictly anaerobic bacteria suggests that sediments might also undergo anoxic conditions that, in turn, could favor the accumulation of PRT in respect to CHO, assuming that fermentation of amino acids is slower than that of sugars from decomposing polysaccharides.  相似文献   

虚拟技术在地震前兆技术系统中的应用     

胡玉良  程冬焱  李惠玲 《震灾防御技术》2015,10(3):688-694

地震前兆技术系统长期稳定和可靠运行对管理人员来说至关重要,本文以山西前兆台网为例,基于VMware虚拟机搭建了地震前兆技术系统,并利用其快闪及克隆功能实现了地震前兆技术系统的快速备份及恢复,提升了地震前兆技术系统故障应急处置能力。  相似文献   

小球藻对5种常用基因工程抗生素的敏感性研究   总被引：14，自引：2，他引：12  

陈颖  李文彬  张利明  孙勇如 《海洋与湖沼》1999,30(5):500-505

于１９９６年以本实验室培养的随圆小球藻为材料,就其对Ｇ４１８,潮霉素,氯霉素,链霉素,卡好霉素等５种抗生素的敏感性进行了研究。结果表明,小球藻对氯霉素,链霉素和卡那霉素敏感,对潮霉素较为敏感,１００μｇ／ｍｌ即０．１９０ｍｍｏｌ／Ｌ的用量可抑制固体培养中小球藻的生长;对Ｇ４１８则高度敏感,３０μｇ／ｍｌ即０．０４３ｍｍｏｌ／Ｌ的Ｇ４１８即可完全抑制固体培养中小藻 的生长,１５μｇ／ｍｌ即０．０２２  相似文献   

The value of instream stable water isotope and nitrate concentration data for calibrating a travel time-based water quality model     

A. Borriero  A. Musolff  R. Kumar  J. H. Fleckenstein  S. R. Lutz  T. V. Nguyen 《水文研究》2024,38(5):e15154

  相似文献   

论计算机不间断电源系统     

杨成林  朱海燕  杨孝宇 《福建地震》1998,(4)

本文讨论了计算机不间断电源系统的原理、性能及其发展趋势,并对计算机不间断电源系统的选型和维护作了探讨。  相似文献   

贡山独龙江地区锡钨矿找矿前景   总被引：1，自引：0，他引：1  

张宗勇 《云南地质》2011,30(1):28-31

贡山县独龙江地区,基础地质工作已发现多处物化探异常,认为该区具有形成和赋存锡钨矿床的地质条件,而与南段腾冲、梁河等地相似,极具寻找锡钨多金属矿潜力。  相似文献   

Structure of microbial communities and hydrocarbon-dependent sulfate reduction in the anoxic layer of a polluted microbial mat     

Abed RM  Musat N  Musat F  Mussmann M 《Marine pollution bulletin》2011,62(3):539-546

The bacterial communities in the anoxic layer of a heavily polluted microbial mat and their growth on hydrocarbons under sulfate-reducing conditions were investigated. Microbial communities were dominated by members of Alphaproteobacteria (27% of the total rRNA), Planctomycetes (21.1%) and sulfate-reducing bacteria (SRB: 17.5%). 16S rRNA cloning revealed sequences beloning to the same bacterial groups with SRB affiliated to the genera Desulfobulbus, Desulfocapsa, Desulfomicrobium, Desulfobacterium and Desulfosarcina/Desulfococcus. The derived enrichment cultures on crude oil, hexadecane and toluene were dominated by SRB. While most SRB sequences of the toluene and hexadecane cultures were related to the sequence of Desulfotignum toluolica, the crude oil enrichment showed a more diverse bacterial community with sequences from the genera Desulfotignum, Desulfobacter, Desulfatibacillus, Desulfosalina, and Desulfococcus. We conclude that the anoxic layer of the studied mats contains a diverse community of anaerobic bacteria, dominated by SRB, some of which are able to grow on hydrocarbons.  相似文献   

基于克隆选择算法的冲压工艺机器人结构优化研究     

李长江  刘海涛  薛琴  王贵 《广东海洋大学学报》2014,(4):84-90

冲压上下料机器人的结构优化设计,通常涉及多个优化参数,采用传统的优化方法往往由于优化目标函数的复杂性不能得到理想的效果。提出基于克隆选择算法的机器人本体结构优化方法,依托有限元ANSYS Workbench平台得到上下料机器人关键零部件的全局最优本体结构。通过与ANSYS Workbench自带优化算法的比较可知:在不增加结构质量的情况下,能获得更高的刚度和强度,从而有效提高机器人的机械性能。实验测试证明了该方法有效可行。  相似文献   

Constraining water age dynamics in a south-eastern Australian catchment using an age-ranked storage and stable isotope approach     

Alexander J.V. Buzacott  Ype van der Velde  Claudia Keitel  R. Willem Vervoort 《水文研究》2020,34(23):4384-4403

Improving our knowledge of the travel times of water through catchments is critical for the management and protection of water resources and to improve our understanding of fundamental catchment behaviour. In this study we use the age-ranked storage framework StorAge Selection (SAS) to investigate travel times in the Corin catchment, a headwater catchment in the south-east of Australia covered by native Eucalyptus species. Few studies have applied the SAS framework globally and in energy-intensive areas where catchment losses are heavily in favour of evapotranspiration relative to streamflow. A combination of observed and modelled values of oxygen-18 (δ¹⁸O ), the stable isotope in water, are used to constrain storage selection preferences of streamflow and evapotranspiration and the size of the catchment active storage. The highest performing parameter combinations that could reproduce δ¹⁸O in streamflow were dependent on a strong preference for young water in evapotranspiration, and a mixture of weak young and old water preference in streamflow. The mean travel time of streamflow over the study period 2007–2019, weighted by the flow rate, is limited to within a probable range of 2.81–9.77 years. The size of the active storage, a key parameter in the SAS framework, was poorly identified, and in combination with the isotopic inputs into the model, contributed to the uncertainty of the results. We discuss the implications of the results with respect to the study area, as well as within the context of SAS research globally and identify ways to improve the modelling process.  相似文献