基于BOFDA的地面塌陷变形分布式监测模型试验研究          下载免费PDF全文

卢毅  于军  龚绪龙  施斌  王宝军  季峻峰 《高校地质学报》2018,24(5):778

地面塌陷变形作为一种分布广泛的地质灾害已成为目前城市发展中亟待解决的一个问题。文章使用布里渊光频域分 析（BOFDA）技术对地面塌陷变形进行分布式监测模型实验研究。利用自制的地面塌陷物理模型,对不同类型、不同厚度 土体在塌陷过程中的变形进行分布式光纤监测,并对其试验结果进行对比分析。结果表明：基于BOFDA分布式光纤传感技 术可有效捕捉到地面塌陷变形的发生和发展过程,并较为准确地反映出地面的塌陷变形规律。研究结果为该技术在地面塌 陷变形监测的推广应用提供一定的参考依据。  相似文献   

高压密闭消解-电感耦合等离子体光谱和质谱联合测定海洋地质样品中52种元素   总被引：4，自引：0，他引：4  

高晶晶  刘季花  李先国  鄢全树  王小静  汪虹敏 《海洋学报(英文版)》2017,36(1):109-117

An improved analytical method to determine the content of 52 major, minor and trace elements in marine geological samples, using a HF-HCl-HNO_3 acid system with a high-pressure closed digestion method(HPCD), is studied by an inductively coupled plasma optical emission spectrometry(ICP-OES) and an inductively coupled plasma mass spectrometry(ICP-MS). The operating parameters of the instruments are optimized, and the optimal analytical parameters are determined. The influences of optical spectrum and mass spectrum interferences, digestion methods and acid systems on the analytical results are investigated. The optimal spectral lines and isotopes are chosen, and internal standard element of rhodium is selected to compensate for matrix effects and analytical signals drifting. Compared with the methods of an electric heating plate digestion and a microwave digestion, a high-pressure closed digestion method is optimized with less acid, complete digestion,less damage for digestion process. The marine geological samples are dissolved completely by a HF-HCl-HNO_3 system, the relative error(RE) for the analytical results are all less than 6.0%. The method detection limits are 2–40μg/g by the ICP-OES, and 6–80 ng/g by ICP-MS. The methods are used to determine the marine sediment reference materials(GBW07309, GBW07311, GBW07313), rock reference materials(GBW07103, GBW07104,GBW07105), and cobalt-rich crust reference materials(GBW07337, GBW07338, GBW07339), the obtained analytical results are in agreement with the certified values, and both of the relative standard deviation(RSD) and the relative error(RE) are less than 6.0%. The analytical method meets the requirements for determining 52 elements contents of bulk marine geological samples.  相似文献   

Spectral Reflectance Analysis of the Caribbean Sea     

《Geofísica Internacional》2014,53(4):385-398

Reflectance spectral curves were analysed by a derivative method. Derivative reflectance spectra revealed concealed peaks of both reflectance and absorption curves of Caribbean seawater and elements contained within it. Reflectance curves showed a predominant blue colour (400–500 nm) characteristic of Caribbean oligotrophic waters, conspicuous peaks result from the optical properties of chlorophyll a and seawater. Reflectance curves had a similar spectral response. This paper analyses reflectance spectra of surface seawater at 31 stations in the Caribbean Sea during the summer of 2001.  相似文献   

基于桩身应力测试的静压PHC管桩贯入机制   总被引：3，自引：0，他引：3  

寇海磊  张明义 《岩土力学》2014,35(5):1295-1302

压桩过程中PHC管桩侧摩阻力与端阻力的分离是制约其贯入机制及承载力研究的瓶颈。通过桩身预埋准分布式FBG光纤传感器,对贯入成层土地基中5根足尺开口PHC管桩侧摩阻力及端阻力发展变化情况进行了监测。试验表明,准分布式光纤传感测试技术现场可操作性强,粗放施工环境下贯入阻力分离效果较为理想。成层土地基中压桩力曲线基本反映地层土性变化,桩端土层性状对压桩力影响较大。硬质土层界面处试桩压桩力平均增幅约为64.06%,端阻力受地层变化影响更为显著,平均增长幅度约为97.41%,侧摩阻力平均增长幅度约为17.92%;桩端位于非硬质土层试桩压桩力变化不明显。贯入过程中现场足尺试验桩身应力变化不同于室内模型试验,桩身上、下部侧摩阻力发挥的力学机制不同。受现场粗放施工条件及深度方向土层变化影响,贯入成层土地基中桩侧摩阻力临界深度现象不明显。  相似文献   

基于CALIPSO星载激光雷达的中国沙尘气溶胶观测   总被引：2，自引：0，他引：2  

徐成鹏  葛觐铭  黄建平  付强  刘华悦  陈斌 《中国沙漠》2014,34(5):1353-1362

基于2006年6月至2012年5月无云条件下CALIPSO星载激光雷达观测资料,分析中国典型地区（塔克拉玛干沙漠、柴达木盆地、戈壁区和华北）沙尘气溶胶分布。结果表明：塔克拉玛干沙漠和戈壁区为沙尘天气发生频率高值区,且前者在各高度层的沙尘发生频率都大于后者。沙尘发生呈季节性分布。塔克拉玛干沙漠在春季沙尘发生频率最大,抬升最高可至10 km,冬季频率最小,高度最低,主要分布在3 km以下。戈壁区在春季沙尘发生频率、抬升高度最大,冬季抬升高度最低,但低层发生频率大于夏、秋两季。在塔克拉玛干沙漠,沙尘光学厚度春季最大约为0.44,冬季最小约为0.17,春,冬季消光系数峰值最大,可达0.25 km^-1,且随高度的递减率大于夏,秋季。在戈壁区和柴达木盆地,沙尘光学厚度春季最大、秋季最小。在华北,沙尘光学厚度春季最大、夏季最小,消光系数在2 km以上春季最大,这主要是由于春季远距离高空传输到华北的沙尘量最多。塔克拉玛干沙漠与柴达木盆地的退偏比为0.2~0.35,戈壁区为0.16~0.28,可能是由于塔克拉玛干沙漠的物质组成与柴达木盆地相同,而与戈壁区不同。华北因低层沙尘与其他气溶胶混合导致退偏振比廓线随高度递增。4个区域对流层上部退偏比全为0.2,表明高空气溶胶可能为来自相同源区的沙尘。  相似文献   

基于AERONET的西亚地区气溶胶光学特性          下载免费PDF全文

谢丽凤  许潇锋  潘诗娴  罗天阳  杨语迪  杨晓玥  吴浩  戚佩霓  蔡乐天 《大气科学学报》2022,45(1):148-160

利用AERONET 10个站点的Level2数据分析得到2010-2017年西亚地区多个气溶胶参数(光学厚度(Aerosol Optical Depth,AOD)、吸收光学厚度(Absorption Aerosol Optical Depth,AAOD)、波长指数α、粒子体积谱和单次散射反照率(Single Scatt...  相似文献   

光学遥感影像的山地冰川运动速度分析方法   总被引：6，自引：5，他引：1  

黄磊  李震 《冰川冻土》2009,31(5)

山地冰川随着地形、气候变化等因素不断运动,及时准确的获取冰川运动速度是研究山地冰川特性以及冰川灾害预警的重要组成部分.将光学影像相关技术应用于冰川的运动监测,并在运算中提出了"移动格网"方法.选用相同区域时间序列影像,一幅影像上用格网分割冰川区域,每个小单元格在另一幅影像上根据冰川表面纹理特征进行相关分析,取相关性最大的对应单元格作为变化后的位置,两幅图像由单元格位移量计算运动速度.影像上格网逐步移动,直至完成整个冰川区域的速度解算.选用天山区域一块冰川间隔10a的光学影像,对方法进行了验证.  相似文献   

卫星激光测距仪发散角系统的设计     

项清革  卫志斌  程伯辉  瞿锋  王谭强 《测绘科学》2004,29(5):44-46

介绍了房山人卫站近期对人卫激光测距仪发散角系统改造和完善过程中所开展的一些工作。首先针对实际工作中不同高度的观测卫星,按照光学原理设计了一套由成像系统、传动系统以及控制系统组成的自动调整发散角的装置,通过调控力矩电机的电压,经联轴件带动丝杠旋转,使滑块前后移动,从而改变成像系统,使激光束的发散角产生变化。其次为了验证系统设计的合理性,对本套装置进行了相关的实验。从实际的观测情况可以看出,改造后的发散角调整系统在提高整机观测能力方面有明显作用。  相似文献   

Recent Progresses in Atmospheric Remote Sensing Research in China-- Chinese National Report on Atmospheric Remote Sensing Research in China during 1999-2003     

QIU Jinhuan  CHEN Hongbin 《大气科学进展》2004,21(3):475-484

Progresses of atmospheric remote sensing research in China during 1999-2003 are summarily introduced.This research includes: (1) microwave remote sensing of the atmosphere; (2) Lidar remote sensing; (3)remote sensing of aerosol optical properties; and (4) other research related to atmospheric remote sensing,including GPS remote sensing of precipitable water vapor and radiation model development.  相似文献   

A Simple Method to Minimize Orientation Effects in a Profiling Radiometer     

T. Suresh  Madhubala Talaulikar  Elgar Desa  S. G. Prabhu Matondkar  T. Srinivasa Kumar  Aneesh Lotlikar 《Marine Geodesy》2013,36(4):441-454

Marine optical parameters required for ocean color satellite applications must be measured with high accuracy and errors within the permissible limits. These stringent requirements demand careful measurements of optical parameters. Though the free-fall radiometer is found to be a better option for measuring underwater light parameters as it avoids the effects of ship shadow and is easy to operate, the measurements demand profiling the radiometer vertical in water with minimum tilt. Here we present the results of our observations on the tilts of the radiometer from the measurements in the Arabian Sea. Since there is hardly any study carried-out on the tilt of the profiling radiometer, the result of this study will help in the better design of such marine instruments. The tilt of the radiometer near the surface of the water is attributed to the mode of deployment and environment parameters, while the tilt at depth of the water is influenced by the density variations of the water. Here we also demonstrate a method of deploying the instrument that minimizes the tilt of the instrument at the surface layer of the water.  相似文献