SLJ-100DH型井下数字三分向力平衡加速度计装置研制

介绍了新研制的井下数字三分向力平衡加速度计装置技术性能、工作原理,分析讨论了仪器的特点。     

A comparative study between China and U.S. on seismic design philosophy and practice of a long span arch bridge

This paper presents the first of a series of case studies on the seismic design of long span bridges （cable-stayed bridges, suspension bridges and arch bridges） under a cooperative research project on seismic behavior and design of highway bridges between the State Key Laboratory for Disaster Reduction in Civil Engineering, Tongji University and the Multidisciplinary Center for Earthquake Engineering Research, University at Buffalo. The objective of this series of case studies is to examine the differences and similarities on the seismic design practice of long span bridges in China and the U.S., to identify research needs and to develop design guidelines beneficial to bridge engineers in both countries. Unlike short to medium span bridges, long span bridges are not included in most seismic design specifications, mainly because they are location dependent and structurally unique. In this paper, an available model of a steel tied half through arch bridge with a main span of 550m in China is discussed. Analysis is focused on comparisons of the seismic responses due to different ground motions. Seismic design criteria and seismic performance requirements for long span bridges in both countries were first introduced and compared, and then three near field earthquake records with large vertical components were selected as the excitations to examine the seismic behavior and seismic vulnerability of the bridge. Results show that （1） the selected near field ground motions cause larger responses to key components （critical sections） of the bridge （such as arch rib ends） with a maximum increase of more than twice those caused by the site specific ground motions; （2） piers, longitudinal girders and arch crowns are more vulnerable to vertical motions, especially their axial forces; and （3） large vertical components of near field ground motions may not significantly affect the bridge＇s internal forces provided that their peak acceleration spectra ordinates only appear at periods of less than 0.2s. However, they may have more influence on the longitudinal displacements of sliding bearings due to their large displacement spectra ordinates at the fundamental period of the bridge.     

Kinematic source model for simulation of near-fault ground motion field using explicit finite element method

1 Introduction The prediction of broadband near-fault ground motion is an important aspect of seismic risk analysis, and is essential for the evaluation of urban seismic safety. Many methodologies are used to model the near-fault ground motions, such as the Green function method, ?nite element (FE) / ?nite difference (FD) method and a hybrid method (Aagaard, 1999; Oprsal and Zahradnik, 2002; Oprsal et al., 2003 a and b). In the hybrid method, the FE / FD method is used to model the low fr…     

Report on 34 Ga SHRIMP Zircon Age from the Yuntaishan Geopark in Jiaozuo, Henan Province

1 Introduction According to recent researches, the North China Craton consists of three parts: the eastern block, western block and central zone (Zhao, 2001; Wilde et al., 2002). Paleoarchean continental blocks and zircon residuals have only been found in a few regions, such as Anshan, East Liaoning (Liu et al., 1992; Song et al., 1996; Wan et al., 2002, 2005), Caozhuang, East Hebei (Liu et al., 1992) and Xinyang, West Henan (Zheng et al., 2004), which are mainly distributed in the east…     

新一代天气雷达轴角盒故障的分析处理

CINRAD/SA天气雷达在PPI扫描过程中天线来回摆动,导致雷达无规律出现方位扇形范围无回波,雷达不能正常发挥其有效作用。为查找故障原因,从新一代天气雷达伺服系统信号流程入手,结合雷达基数据分析软件,分析雷达天线运行轨迹,通过信号流程中关键点参数的测量和比较,发现问题出现在轴角编码盒方位环节,导致轴角盒串行方位轴角数据输出不连续,造成雷达无规律出现方位扇形范围无回波。通过对此类故障分析思路与处理经验的总结,对台站级雷达技术保障提供借鉴。     

利用MODIS资料遥感水体上空气溶胶粒子尺度的数值试验

利用卫星探测辐射的光谱依赖性来反演大气气溶胶粒子尺度分布,首先要建立反演算法并检验其可行性。本文参照文献[1]对暗的海洋上空MODIS资料的处理方法,针对大陆水库上空卫星探测MODIS辐射信号,利用6S(Second Simulation of the Satellite Signal in the Solar Spectrum)辐射模式建立一个查算表(Look-up table:LUT)来反演大气气溶胶粒子尺度分布;然后通过数值试验对所建立的查算表进行检验,讨论其方法的可行性。数值试验结果表明,查算表对大陆性气溶胶尺度分布有反演能力,但拟合误差sεl值随着气溶胶光学厚度的增加而增加。     

广州城区晚全新世环境变迁与人类活动

对广州市越秀区解放中路考古遗址剖面进行了年代学、岩性、硅藻和软体动物鉴定等研究,发现广州珠江北岸古城区南部在先秦时期为河道及河口湾湿地/洼地;因河流-河涌的淡水注入使河口盐度降低,故而沉积物中未见较高盐度的微体生物,仅发现了河口型咸水-半咸水硅藻;此时堆积的贝壳大多为淡水种,半咸水种少见,表明先秦(东周)时期,广州地区...     

基于多源数据融合的山地实况业务体系建设

【目的】探讨和实践基于多源数据融合的山地实况业务体系建设,以提高山地地区的监测、预警和灾害应对能力。【方法】通过分析山地地区面临的地理环境、气象条件以及自然灾害的特点,以及基于对已有实况业务发展的现状分析,建设全面、精准、实时的山地实况业务体系。【结果】明确贵州省实况产品建设方向并介绍了在山地实况业务体系建设中的技术路线,包括数据采集、传输、处理、展示、全流程监控等关键步骤,以及各环节的技术创新和方法改进。最后分析了面向重大服务、重点行业、重要区域开展有针对性的实况产品服务时仍需重点解决的问题。【结论】该文的研究成果为山地区域的实况业务体系建设提供了思路和方法,对于提升山地区域的灾害管理水平具有实际应用价值。     

蜀南地区下三叠统飞仙关组沉积相

蜀南地区飞仙关组的沉积相类型主要有浑水陆棚相与清水陆棚相,东部两者交替发育,中西部则主要为浑水陆棚相。浑水陆棚相以半局限海亚相为主,包括三个微相;清水陆棚相可分为颗粒滩、滩间、潮坪和内缘斜坡等四个亚相,包括若干微相。飞一段全区为清水陆棚相;飞二段全区均为浑水陆棚亚相的泥质半局限海微相;飞三段,西部为浑水陆棚相,东部为清水陆棚相,其间发育灰泥质半局限海微相;飞四段基本为泥质半局限海微相。飞一时,区内中部有一近南北向的台内凹槽,沿凹槽边缘鲕粒滩较发育。研究区以西的康滇古陆和龙门山岛链与华蓥山断裂带控制着区内沉积相展布,当康滇古陆和龙门山岛链构造活跃时全区发育浑水陆棚,华蓥山断裂带活动时东部发育清水陆棚;当康滇古陆、龙门山岛链与华蓥山断裂带构造的活动性都较低时,全区以清水陆棚为主。     

面向野外地质调查工作的道路提取方法研究

为弥补传统的依靠管理组织、法律、经济、教育等进行对野外地质工作安全管理工作的不足,通过百度SDK采集GPS步行轨迹数据,基于单向GPS轨迹数据的特点,进行轨迹的分割分段处理.最后利用BP神经网络算法拟合道路,通过反复实验确定BP网络的参数配置信息.并以中国地质大学西区为研究区域,提取路网信息,验证算法的有效性和实用性....