共查询到20条相似文献，搜索用时 218 毫秒
1.
2.
地震台阵流动地震仪的检测与标定方法研究 总被引：2，自引：1，他引：1
流动地震仪组成的台阵观测系统已经成为地下结构、物性探测的基本工具,高质量观测数据的获取是以地震仪的性能为基础的。本文结合中国地震科学探测台阵系统建设与维护实践,介绍了科学探测台阵系统采用的几项检测标定技术,包括超低频振动台标定、仪器一致性组网检测、白噪声标定和现场快速仪器检测,形成了一套适合地震流动台阵仪器的检测标定方法,并在观测实践中获得较好的应用。 相似文献
3.
油气是国家发展的重大战略资源.随着近年来对油气的开发利用,几大油气田都出现了严重的套损问题,严重影响了油气的开发,造成了巨大的经济损失.因此,寻找一种合理有效的方法来对套管状况进行预测并针对的采取预防措施,对延长油水井的工作寿命、降低损失从而提高生产效率具有重要意义.首先介绍了贝叶斯神经网络的基本原理,以及ARD技术与模型比较技术;其次,与经典BP神经网络进行对照实验,验证贝叶斯神经网络在过拟合方面的优势;根据模型证据确定最优神经网络结构,整理大庆油田南一区西西区块部分井数据进行预测分析,获得套损因素相关权重.结果显示:油井与水井预测结果的准确率分别为82.86%和73.85%,具有较高的准确性;该区域套损的主控因素为高压注水导致的断层开启导水,油田方面应采取提高固井质量、选择合理的注水压力等措施来预防套管损坏. 相似文献
4.
介绍了即将投入使用的一种新型数字地震测深仪器系统的情况;还较详细地介绍了该仪器系统的各种装置的规格和性能,并指出这些仪器构成了一套较完整的野外接收—野外基地监视回放—实验室回放处理的数字地震测深仪器系统。 相似文献
5.
本文介绍了桩基动态检测仪器设备的原理及性能，该仪器集瞬态冲击加速度，速度，位移测量，多频段抗混滤波，非线性自动增益放大，冲击作用力测量于一体，是一套（包括小落锤、中落锤）较完整的小应变桩基检测仪器。 相似文献
6.
7.
《地震工程学报》2018,(Z1)
地震氡观测仪检测平台是"十三五"地震地下流体学科观测仪器检测平台的重要组成部分,是地震流体学科第一个检测平台。本文对其设计理念、建设内容进行介绍。平台校准单元设计符合《测氡仪检定规程JJG825-2013》技术要求,氡浓度的测量范围达到800～15 000Bq/m3,扩展不确定度达到8%(k=2),72h稳定性优于5%,检测单元设计将承担新研发仪器和复检仪器的性能检测与质量评估工作。整个平台建成后,将满足全国正在运行的地震氡观测台网300多项氡观测仪的校准需求,为每年30～50套氡观测仪提供更新或新建氡观测台站的仪器提供性能检测服务,保证地震行业氡观测质量。 相似文献
8.
9.
喀什地磁台目前已配备了两套相对记录仪器与两套绝对观测仪器.为了解不同仪器观测精度的异同,以确定合理的仪器组合方式,本文对比了两套记录仪器观测到的日变形态和极值时间,以及两套绝对观测仪器对相同的相对记录仪器测定的基线值.分析结果表明,FGE磁力仪和Mingeo DIM磁力仪精度较高,可作为第一观测组合,另两套仪器町作为喀什地磁台的第二观测组合. 相似文献
10.
11.
笔者分析了３９例ＭＲＩ脑内海绵状血管瘤病人的图像资料，并对ＣＴ、ＭＲＩ、ＤＳＡ的诊断价值进行了比较，ＭＲＩ多次出血信号特征和ＣＴ钙化灶是其特点，笔者认为ＣＴ、ＭＲＩ综合分析，是对本病进行无损伤性检查的首选方法。 相似文献
12.
Intense research and refinement of the tools used in performance-based seismic engineering have been made,but the maturity and accuracy of these methods have not been adequately confirmed with actual data from the field. The gap between the assumed characteristics of actual building systems and their idealized counterparts used for analysis is wide. When the randomly distributed flaws in buildings as they exist in urban areas and the extreme variability of ground motion patterns combine,the conventional procedures used for pushover or dynamic response history analyses seem to fall short of reconciling the differences between calculated and observed damage. For emergency planning and loss modeling purposes,such discrepancies are factors that must be borne in mind. Two relevant examples are provided herein. These examples demonstrate that consensus-based analytical guidelines also require well-idealized building models that do not lend themselves to reasonably manageable representations from field data. As a corollary,loss modeling techniques,e.g.,used for insurance purposes,must undergo further development and improvement. 相似文献
13.
Intense research and refinement of the tools used in performance-based seismic engineering have been made, but the maturity and accuracy of these methods have not been adequately confirmed with actual data from the field. The gap between the assumed characteristics of actual building systems and their idealized counterparts used for analysis is wide. When the randomly distributed flaws in buildings as they exist in urban areas and the extreme variability of ground motion patterns combine, the conventional procedures used for pushover or dynamic response history analyses seem to fall short of reconciling the differences between calculated and observed damage. For emergency planning and loss modeling purposes, such discrepancies are factors that must be borne in mind. Two relevant examples are provided herein. These examples demonstrate that consensus-based analytical guidelines also require well-idealized building models that do not lend themselves to reasonably manageable representations from field data. As a corollary, loss modeling techniques, e.g., used for insurance purposes, must undergo further development and improvement. 相似文献
14.
Seismic evaluation of rocking structures through performance assessment and fragility analysis 总被引：2，自引：2，他引：0
Numerical studies have been conducted for low- and medium-rise rocking structures to investigate their efficiency as earthquake-resisting systems in comparison with conventional structures. Several non-linear time-history analyses have been performed to evaluate seismic performance of selected cases at desired ground shaking levels, based on key parameters such as total and flexural story drifts and residual deformations. The Far-field record set is selected as input ground motions and median peak values of key parameters are taken as best estimates of system response. In addition, in order to evaluate the probability of exceeding relevant damage states, analytical fragility curves have been developed based on the results of the incremental dynamic analysis procedure. Small exceedance probabilities and acceptable margins against collapse, together with minor associated damages in main structural members, can be considered as superior seismic performance for medium-rise rocking systems. Low-rise rocking systems could provide significant performance improvement over their conventional counterparts notwithstanding certain weaknesses in their seismic response. 相似文献
15.
This paper serves as the missing piece in a more fuller understanding about economic losses from marine pollution, and demonstrates what losses have been estimated in the literature. Biological effects from marine pollution are linked with resulting economic effects and losses. The merging of these two areas is usually absent in studies of marine pollution losses. The literature has examined several effects due to marine pollution: damages due to harvest closures-restrictions, damages from consumption of unsafe seafood, damages due to decreased recreational activity, and damages related to waterfront real estate adjacent to contaminated water. Overall, marine pollution can and has resulted in sizable economic effects and losses. On the basis of the literature there is adequate justification for public policy actions to curb marine pollution, require inspection of seafood for toxic substances, and preserve marine water quality and sensitive marine environments. 相似文献
16.
Elastic wave inverse scattering in nondestructive evaluation 总被引：7，自引：0，他引：7
James H. Rose 《Pure and Applied Geophysics》1989,131(4):715-739
Ultrasonic detection and characterization of flaws in metals and ceramics is of considerable technological interest. Scattering and inverse scattering theories have recently been applied to these tasks in a systematic manner and considerable progress has resulted. This paper first reviews briefly the development of scattering and inverse scattering methods in the AF/DARPA Program in Quantitative Nondestructive Evaluation.2 Then one particular inverse method studied in that program, the inverse Born approximation, is discussed in detail. Progress is reviewed and the ability of the method to distinguish volumetric and crack-like flaws is demonstrated in simple cases.This work was sponsored by the Center for Advanced Nondestructive Evaluation, operated by the Ames Laboratory, USDOE, for the Air Force Wright Aeronautical Laboratories/Materials Laboratory under Contract No. W-7405-ENG-82 with Iowa State University. 相似文献
17.
Characteristics of floods on the territory of Russia with regard to their natural and socioeconomic parameters 总被引：1，自引：0，他引：1
Parameters of 123 floods on the territory of the Russian Federation are analyzed, including the dates of young floods, numbers
(frequency), duration, genetic type of floods, inundated land areas, total area of regions affected by flood, coordinates
of their centers, number of population in these regions, total number of affected people, number of evacuated and killed people,
number of buildings in inundation zone, and monetary damage. It is shown that material and human damages caused by rainfall
floods and snowmelt floods in rivers are several orders of magnitude greater than the damages caused by the most common spring
floods. Collation maps of main flood parameters have been prepared and analyzed; the areas of floods of main genetic types
have been revealed and mapped and graphs of seasonal and long-term variability of flood parameters has been calculated. 相似文献
18.
损伤和缺陷对海洋平台抗冰抗震性能的影响 总被引：1，自引：0，他引：1
现役导管架式海洋平台可能会存在裂纹、凹痕、腐蚀等缺陷和损伤,并可能受到海洋生物附着及地基土冲刷的影响,这些问题将减小构件强度或者放大荷载作用.取一座导管架海洋平台为例,应用动力时程及整体推进法进行分析,对比损伤前后动冰力作用下结构响应、结构抗冰能力曲线及剩余强度储备系数,并取3个地震波对损伤前后结构的地震响应、抗震能力曲线、抗震安全裕度系数进行对比.结果显示损伤和缺陷极大地降低了海洋平台抗冰抗震性能,对现役海洋平台的检测和维修也有一定借鉴意义. 相似文献
19.
TAN Ying ZHANG Wei LI Qingxia YANG Xiaoqing ②IRTCES ③Department of River Studies. The Yangtze River Scientific Research Institute ④Sichuan Provincial Design Institute of Water Conservancy Hydroelectric Power ⑤Institute of Water Conservancy Hydroelectric Power Research. 《国际泥沙研究》1991,(2)
When gravel bed load deposits are sluiced from hydraulic structures, the mo- tion of bed load over the apron, as is well known, may consist of sliding, rolling and saltation. At times, saltation may become so intensive that gravels have been observed to jump clear out of the water surface. The movement of gravel bed load may cause serious damages to the hydraulic structures through abrasion and im- pact. The extent of damage depends upon a number of factors, such as rock prop- erties of gravels, flow conditions, configuration as well as the strength of materials of hydraulic structures. In most cases the movement of gravel bed load takes place in ribbons in plan, consequently, the lateral distribution of damages is uneven, and protective measures to be adopted against abrasion and impact should be applied to the key part most frequently attacked by the gravel bed load. Possible repair should be anticipated in the layout of structures in order to facilitate the operation. 相似文献