浅析全站仪加常数、乘常数     

王福学  韩庆龙  韩正阳 《测绘与空间地理信息》2011,34(2):248-250

介绍了全站仪在应用中两项重要指标(加常数、乘常数)的常规检测方法及改正方法,并分析了目前全站仪应用中基层测量员存在的误区,望能引起广大基层测量员的重视.  相似文献   

探地雷达对地下防空洞的探测研究     

谷松 《城市地质》2011,6(3):47-48

本文简述了探地雷达技术的基本原理及其在阜新高德东山探测防空洞的应用。  相似文献   

基于风廓线雷达资料的暴雪天气过程分析     

张彩英 《气象与环境科学》2016,39(4):80-85

利用常规观测资料和风廓线雷达产品对平顶山市2014年2月5—6日的暴雪天气过程进行诊断分析,结果表明:欧亚地区"两槽一脊"的环流背景下,700 h Pa西南急流、850 h Pa切变线和地面中尺度辐合线是这次暴雪的影响系统。风廓线雷达水平风资料可以清楚地展示暴雪过程风场"天南地北"的垂直结构及其变化特点。2500 m以上出现西南急流,同时720 m以下出现东北风,降雪开始。2500 m以上西南急流最大风速达到20m·s~(-1),近地面出现12 m·s~(-1)的东北风,降雪开始加大;近地面东北风减弱,降雪减弱;西南急流消失,近地面层出现偏北风,降雪停止。垂直速度的大小与降雪的强弱一致,降雪越强,速度越大;垂直速度小于0.5 m·s~(-1),降雪停止。大气折射率常数C2n在-144~-120 d B且接地,为降雪时段。降雪越强,C2n越大;C2n小于-144 d B时,降雪停止。垂直速度、折射率结构常数等指标的变化能够反映降雪的开始、发展和结束及降雪的强度,为精细化预报提供参考。  相似文献   

Effects of varying estuarine conditions on the sorption of phenanthrene to sediment particles of Yangtze Estuary     

《Marine pollution bulletin》2013,77(1-2):139-145

The sorption of phenanthrene on the Yangtze Estuary sediment was studied under varying conditions of particle size, sediment organic contents, salinity, and dissolved organic matter (DOM) concentrations. Small sediment particles showed higher trapping capacity for phenanthrene due to the higher organic contents associated. The organic carbon-based partition coefficient of phenanthrene to the Yangtze Estuary sediment was obtained as 7120 L/kg, lower than the values for other soils or sediments reported in previous studies. The magnitude and direction of the salt effect were complicated by the specific DOM studied. The sediment sorption capacity was greatly increased in saline water in the absence of DOM but decreased in the presence of DOM. Given the conditions in the Yangtze Estuary, the equilibrium sorption of phenanthrene would be decreased with increasing salinity. Overall, the nature and content of both sediment-bound and dissolved organic matter dominate the sorption of hydrophobic organic contaminants in the estuary.  相似文献   

Kinetics of Methyldiethanolamine Mineralization by Using UV/H2O2 Process     

Sabtanti Harimurti  Anisa Ur Rahmah  Abdul Aziz Omar  Murugesan Thanapalan 《洁净——土壤、空气、水》2013,41(12):1165-1174

The UV/H₂O₂ is one of the popular techniques in the advanced oxidation processes (AOPs) and has been applied in the wastewater treatment during recent two decades. UV exposure on the H₂O₂ generate highly reactive hydroxyl radicals (OH^?), which are used to degrade organic contaminants through oxidation processes in wastewater. This present study involves the estimation of hydroxyl radical rate constants of methyldiethanolamine (MDEA) mineralization at different temperatures by using UV/H₂O₂ in aqueous solution. Laboratory experiments have been conducted and the profile of MDEA mineralization has been established. The hydroxyl radical rate constants and the activation energy of mineralization process have been calculated. The estimated hydroxyl rate constants and the activation energy are in good agreement with those reported in the literature.  相似文献   

储层砂岩波阻抗及拉梅常数实验研究   总被引：2，自引：0，他引：2  

胡作维  黄思静  单钰铭  裴昌蓉  张亚洲 《地球科学与环境学报》2006,28(4):54-57

地层条件下应用岩石物理参数测试系统(MTS)测试了岩石纵横波速度,结合已研究成果,根据实验数据和计算结果总结了波阻抗和拉梅常数与不同地层条件的关系,得到地表条件下岩样(饱气)的波阻抗随岩石孔隙度的增加而减小。同一个岩样(饱水)的波阻抗随着模拟地层深度的增加而增加。在各自相对应的模拟地层深度条件下,饱水岩样的纵波阻抗和拉梅常数值均明显大于饱气岩样的数值,但横波阻抗变化很小。  相似文献   

Maximal mass and size of celestial bodies born from superstrings     

Corrado Massa 《Astrophysics and Space Science》2007,310(3-4):209-210

The generalized Buchdahl inequality in the presence of a positive cosmological constant gives rise to a constraint on the mass density of celestial bodies. We find that such a constraint implies an upper bound on the mass and radius of spherical celestial bodies born from macroscopic superstrings. We obtain a maximal mass of about 10¹⁵ solar masses and a maximal radius of about 80 million light years, not far from the observed mass and size of the largest structures in the universe, viz. the superclusters of galaxies.  相似文献   

一种新的阶梯水平井段轨道设计模型          下载免费PDF全文

陈天柱  陆洪智  吴翔  方圆  王成立 《探矿工程》2016,43(2):36-38,42

对于开发有一定高度差的多个薄油层,阶梯水平井较普通的定向井和水平井,节约了钻井成本,提高了单井的开采效率。分析了现有的阶梯水平井的设计模型,采用恒工具面模型进行三维阶梯水平井的轨道设计,以上下靶点的井斜角和方位角作为已知量,造斜工具的造斜率和安装角作为控制因素,将过渡点的井斜角和方位角作为待求参数。所设计的三维井眼轨道,通过计算示例表明,可用于设计阶梯水平井段。  相似文献   

Deriving a practical form of IDF formula using transformed rainfall intensities          下载免费PDF全文

Kee‐Won Seong 《水文研究》2014,28(6):2881-2896

A general form of formula is presented for the rainfall Intensity–Duration–Frequency (IDF) relationship. This formula is derived from the nearly normal probability distribution function of transformed intensities. In order to transform the raw intensities, a correcting non‐constant spread technique, the Kruskal–Wallis statistic, and the Box–Cox transformation are adopted. These transformations enable to express a simpler model for the IDF formula that agrees well with traditional IDF relationships. Since the proposed method allows the estimation of any percentile value of intensities with a single equation, the intensity percentile at arbitrary duration can be generated easily. The validity of the formula derived by means of the proposed method is assessed using data from major weather stations in Korea. The results show that the percentile intensities produced using the proposed method are in good agreement with those of traditional frequency analysis. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

LGZ-25型全液压螺杆桩钻机的研制与应用          下载免费PDF全文

侯庆国 《探矿工程》2010,37(8):37-40

螺杆桩是一种承载力高、成本低、施工效率高、无污染的新桩型,新研制的LGZ-25型全液压螺杆桩钻机满足了螺杆桩独特的施工工艺要求。结合实际工程实例,介绍了钻机的结构、技术参数、工作原理以及应用效果。  相似文献