Introduction of conditional mean spectrum and conditional spectrum in the practice of seismic safety evaluation in China

This paper aims at implementing and introducing the use of conditional mean spectrum (CMS) and conditional spectrum (CS) as the main input parameters in the practice of seismic safety evaluation (SSE) in China, instead of the currently used uniform hazard spectrum (UHS). For this purpose, a procedure for M-R-epsilon seismic hazard deaggregation in China was first developed. For illustration purposes, two different typical sites in China, with one to two dominant seismic zones, were considered as examples to carry out seismic hazard deaggregation and illustrate the construction of CMS/CS. Two types of correlation coefficients were used to generate CMS and the results were compared over a vibration period range of interest. Ground motion records were selected from the NSMONS (2007–2015) and PEER NGA-West2 databases to correspond to the target CMS and CS. Hazard consistency of the spectral accelerations of the selected ground motion records was evaluated and validated by computing the annual exceedance probability rate of the response spectra and comparing the results to the hazard curve corresponding to each site of concern at different periods. The tools developed in this work and their illustrative application to specific case studies in China are a first step towards the adoption of CMS and CS into the practice of seismic safety evaluation in this country.     

Identification and profiling of microRNAs of Euphausia superba using Illumina deep sequencing

Journal of Oceanology and Limnology - MicroRNAs (miRNAs) are an abundant class of conserved, non-coding small RNAs that play important role in gene regulation at post translational level. There...     

基于神经网络算法的Sentinel-1和Sentinel-2遥感数据联合反演土壤湿度研究

以西班牙萨拉曼卡地区为研究区域,联合Sentinel-1后向散射系数和入射角信息、Sentinel-2光学数据提取的植被指数以及地面实测数据,构建了BP神经网络土壤湿度反演模型,并将该模型应用于试验区土壤湿度反演.结果 表明:1)基于Sentinel-1卫星VV和VH极化雷达后向散射系数、雷达入射角和Sentinel-...     

俯冲带地震动预测模型SMA2020的评估检验实例——2021年2月13日日本福岛县东部海域MW7.1地震

地震动预测具有较大不确定性,利用强震动观测记录对已有地震动预测模型进行检验评估对于模型的合理使用具有重要参考意义。针对2021年2月13日发生在日本福岛县东部海域的M_W7.1地震,基于残差分析和对数似然函数法对俯冲带地震动预测模型SMA2020的路径项和场地项表征合理性、模型的预测精确性进行了评估。得到结果:（1） SMA2020模型对于地震动的路径衰减表征较为合理,在路径项中考虑了莫霍面反射效应,可以更真实地表征俯冲带深源地震的路径效应。（2） SMA2020模型对于PGV的场地效应表征较为合理,但对于PGA及PSA的场地效应表征有所偏差,还需要进一步检验验证。（3） SMA2020模型对于此次板内地震的短周期IM预测精确性要优于中长周期,对于T=1s的PSA预测表现最不佳。研究结果可为模型的潜在使用者提供有价值的辅助信息,也可以为我国地震动预测模型的开发研究提供理论参考。     

典型强震动加速度仪一致性检验

针对两种典型强震动加速度仪,ETNA与MR2002,利用汶川地震强余震流动观测进行了两仪器的一致性检验.通过架设在同一仪器墩上的2种强震动加速度仪在5次余震事件中所获取加速度记录的波形、峰值、傅里叶振幅谱及反应谱的对比分析可知,ETNA仪器记录的峰值加速度与MR2002仪器记录的峰值加速度间的最大相对误差达23.6％,且南北向峰值加速度差异大于东西向和竖向,竖向明显小于两水平向;反应谱及傅里叶谱变化趋势基本相同,只是幅值存在些微差异,且竖向谱值相差最小,明显小于两水平向,反应谱最大相对误差近5％,相对于低频反应谱,高频反应谱差异较大;此外,亦存在两仪器记录时程曲线反向、记录时间长度不等、触发点不同等差异.经分析认为,这些差异主要是由于两种不同仪器性能上的微差异、仪器参数设置不同、以及触发滤波算法不同等因素引起的.     

Modification on Lynett and Liu’s model for internal solitary wave propagation over variable bathymetry

1 INTRODUCTION As an important wave phenomenon, taking place inside the ocean, the internal wave has drawn attentions of many scientists. More and more in- formation about it have been provided by both CTD and ADCP data and the images captured by the synt…     

Nitrogen isotope and content record of Mesozoic orogenic gold deposits surrounding the North China craton

NH4 is the most common form of nitrogen found in rocks and may substitute for K in potas-sic minerals such as biotite, muscovite, and K-feldspar[1,2]. N2 has been observed in fluid inclu-sions, and thermodynamic calculations suggest that N2 is the most c…     

渤海油田深部调驱体系研制及调驱参数优化

为了改善海上油田深部调驱效果,研制一种易于配制、施工简便的由聚合物FP、交联剂和助剂组成的冻胶体系.基于合适的成冻时间和成冻强度,优选适合该油藏条件的冻胶调驱体系配方,即聚合物FP(1 500～2 000mg.L-1)+交联剂(750～1 250mg.L-1)+助剂(1 000～1 500mg.L-1).利用三层非均质岩心进行调驱体系用量和调驱时机对调驱效果影响的评价,优化调驱体系的注入用量和注入时机参数.结果表明:当水驱至目标油藏含水率70%时,随着注入调驱体系用量的增加,采收率增加值越高;基于采出程度和经济效益双重考虑,优选调驱体系的用量为0.2PV;当注入用量为0.2PV调驱体系,油藏综合含水率低于50%条件下,早期注入调驱体系进行深部调驱,采收率增加值高,能够达到很好的调驱效果.