首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 203 毫秒
1.
为解决现有霍尔元件测量系统存在的不足,根据全行程测量数据获取及实时观测的实际需求,研制开发了基于激光三角测量原理的射流式液动潜孔锤激光测量系统。使用该系统对SC-86H型高能射流式液动潜孔锤进行了相关试验,并获得了冲锤的全行程时间分辨数据。通过对试验数据进行处理,得到了冲锤运动的位移-时间和速度-时间关系。结果表明,冲锤的不规则运动发生在周期的回程初始阶段,此不稳定状态增加了冲锤的回程时间,相应地降低了冲锤的冲击频率。冲锤的实际缓冲行程对泵量并不敏感,当泵量从80 L/min增加到220 L/min时,实际缓冲行程仅在5.9~6.8 mm之间变化;实际行程的改变也不会大幅增加冲锤实际缓冲行程,随着冲锤结构行程增加57%(70~110 mm),缓冲行程只增加了7%。该系统可实现全行程测量,并描述实时运动状态。  相似文献   

2.
2003年夏季北冰洋海冰动力学特征参数   总被引:1,自引:3,他引:1       下载免费PDF全文
以2003年的中国第2次北极科学考察的海冰物理过程调查数据为依据,分析了海冰动力学特征并给出体现动力学特征的定量参数。这些参数指出:现场调查的海冰密集度同NOAA冰图上的密集度相比低2~3成,而厚度比1999年的中国首次北极考察结果减少2 m;冰层底面起伏方差约是冰层表面积雪起伏方差的3.8倍;浮冰最快以1 300m/h速度运动并伴随振荡旋转。实测浮冰向东北运动时,旋转角度增加,最大达到37.8o,东南方向旋转时,角度减小;浮冰运动的振荡周期为12.45 h,同该纬度惯性流振荡周期一致,体现出惯性流对浮冰运动的贡献。  相似文献   

3.
冰层厚度传感器及其检测方法   总被引:2,自引:0,他引:2       下载免费PDF全文
水结冰和冰融化过程中的电阻、电容、温度物理参数与被检测冰表面以上的空气层或冰下水层的电阻、电容、温度有一定的差异,有些差异在数值上比较明显。基于这一特点,笔者提出了利用空气、冰与水的物理特性差异实现对冰层厚度及冰下水位接触式检测的新思路,对含有导电杂质的冰、冰-水混合物、水、空气的电阻、电容特性随温度的变化规律进行了初步分析,并得到冰的弱导电性质和冰与水的电容区间单调特性,据此提出了冰层厚度传感器结构及其冰厚检测原理,介绍了新型冰层厚度传感器在实践中的应用。  相似文献   

4.
水塔指示灯     
在供水工程中,用水泵向水塔盛水桶內送水时,一般是设专人来掌握桶內裝水情况,以防止盛水过多,溢出桶外.这样既不方便,也浪费人力.最近一○五勘探队在向水塔送水的工作中,利用了指示灯来控制水塔的裝水情况,这项方法是李树棠同志提出的.装设与使用非常简单,其电路装设如图所示.从电源引用一根单线,通过招示灯,引入水塔上的盛水桶內,联结在铁块上.铁块固定在所需装水的位置上.铁块裝在桶壁上,必需良好的绝缘(铁质或导电物质制成的盛水桶),导线进入桶內亦应与捅保持绝缘.工作中,当水桶內水位上升,遇到铁块时,则使整个电路构成一个完整的通路,指示灯即明  相似文献   

5.
极地冰层硬度特性对铠装电缆电动机械取心钻具反扭装置设计和使用具有重要意义。针对冰层特殊的物理性质,结合材料硬度测试原理,设计了一套可在模拟极地冰层低温条件下测量冰硬度特性的硬度试验台。该试验台由低温冷柜、硬度测试台和数据采集及控制系统3部分组成,其中,数据采集及控制系统隔离在常温环境中,降低了元器件对环境温度的要求。利用该试验台对硬度压头压入冰层的压力和深度进行数据检测,换算得到相应的硬度值。对设计的试验台进行初步实验表明,该试验台工作状态良好,数据准确,可满足对低温材料硬度特性的检测。  相似文献   

6.
现场岩体应力测量和岩体工程应力分析一直是岩石力学研究非常活跃的领域之一,而软弱岩体的现场应力测量与分析又是其中一个亟待解决的难题。针对软弱、破碎岩体现场应力测量技术上的困难,从1983年至1984年,中国科学院武汉岩土力学研究所白世伟、方昭茹等人研制出空心包体式孔壁应变计。空心包体式孔壁应变计是现场地应力测量的一种新式传感器,它利用套孔应力解除法原理通过电阻式应变片测量应变来实现地应力测量,能够在一个钻孔中进行空间应力状态的测量。该传感器利用软塑料空心筒和水下低温粘贴固化剂技术,因此比其它传感器更适合软、碎岩体。该传感器采用均布圆筒表面的出浆孔和完整的安装定向系统,保证了粘贴的方便,也保证了测试的准确可靠,经系统验证,该方法测量地应力的综合误差小于18%。  相似文献   

7.
该仪器共有四组传感器、即扭矩、转速传感器,水泵流量传感器,水泵压力传感器,和钻压传感器。可测钻机扭矩、转速、钻压及水泵流量、压力共五种参数。现在可供水文、水井与地热钻机选用的扭矩传  相似文献   

8.
研制了一款基于PNI磁感式传感器和SCAl00T加速度传感器的矿用全空间钻孔测斜仪。详细论述了系统的总体结构、测量原理及传感器的电路设计;同时分析了系统的误差及其来源,给出了误差补偿模型及其补偿、标定的方法。实验结果表明:该钻孔测斜仪具有体积小、精度高、可靠性高等特点,满足工程的需要。   相似文献   

9.
一、油泵、油马达简单通用工作原理油泵,通常都是用电动机或内燃机(柴油机、汽油机)驱动旋转,它的吸、排油原理,与柱塞式往复水泵吸水和排水原理基本相同(如图5)。在吸入行程时,柱塞被拉出,缸体  相似文献   

10.
介绍了用于大口径钻探的DC型无簧式双作用液动冲击器的结构和工作原理及设计计算结果,给出了其冲程,上阀程和上阀自由行程,下阀程和下阀自由行程的测量及调整方法。  相似文献   

11.
4 000 m DISC深冰芯钻机概述   总被引:1,自引:0,他引:1  
深冰芯钻探(Deep Ice Sheet Coring, DISC)钻机是美国冰芯钻探服务中心(ICDS)开发研制的一款机电钻机, 设计取芯直径122 mm, 钻取深度4 000 m.该系统由两部分组成,包括机械钻进系统和地面支撑系统. 其中, 机械钻进系统由钻机、 电缆、 钻塔和绞车四部分组成, 钻机是该系统的钻探部分, 由6个不同部件(刀盘、 芯管、 筛管、 电机/水泵、 钻机控制板和顶端)组成; 地面支撑系统包括电源、 控制系统、 冰芯处理系统、 钻井液处理系统、 筛管清洗系统、 辅助设备以及安全设备设施. 2006年夏季ICDS在格陵兰Summit营地对该套钻机系统进行了成功试验, 2011年12月31日在西南极冰原(WAIS Divide)成功获取3 405 m深度的冰芯.实践证明, 该套钻机能够满足目前钻探项目的科学需求. 但是, 在西南极冰原主冰孔不同深度钻取同深度副冰孔冰芯的过程中, 钻刀无法在主冰孔壁上侧向钻取新的冰芯孔, 未能如期获取复制的冰芯样品.  相似文献   

12.
论述了将绳索取心,螺杆站,不提钻换钻头三项技术结合在一起的新型取心钻进系统,介绍了系统的结构,工作原理及其技术性能参数和操作要点。  相似文献   

13.
A new soil moisture content sensor coupled with a new matric potential sensor that can operate in the subfreezing environment was used to measure the moisture content and soil matric potential dynamics of Qinghai-Tibetan silty clay. Combined with nuclear magnetic resonance (NMR) technique and thermal resistor temperature probe, the characteristics of unfrozen water content and soil matric potential, and their relationships with temperature were analyzed. The results show that initial water content has an impact on the freezing point and unfrozen water content. The decrease in the initial water content results in a depression in the freezing point. The Qinghai-Tibetan silty clay has more similar unfrozen water content characteristic to clay than to silt. There is approximately 3% of unfrozen water content retained when the soil temperature drops to −15°C. The change of soil matric potential with temperature is similar to that of the unfrozen water content. The matric potential value of the saturated silty clay is approximately −200 kPa when the soil temperature drops to −20°C. The measured matric potentials are significantly lower than the calculated theoretical values based on the freezing point depression. Moisture migration experiment indicates that soil matric potential controls the direction of moisture movement and moisture redistribution (including ice and liquid water) during the soil freezing.  相似文献   

14.
《Earth》2003,60(1-2):131-146
This review paper is mainly concerned with a geochemical investigation of the deepest part of the Vostok ice core between 3310 m, the depth at which the palaeoenvironmental record present in the ice above is lost, and the bottom of the core about 130 m above subglacial Lake Vostok. Two sections constitute this part of the core.The upper section (3310–3539 m depth) still consists of ice of meteoric origin but subjected to widespread complex deformation. This deformation is analysed in light of a δD–deuterium excess diagram and information on microparticles, crystal sizes and chemical elements distributions in that part of the core. Such ice deformation occurred when the ice was still grounded upstream from Vostok station in a region with subfreezing temperatures.The lower section from 3539 m to the bottom of the core at 3623 m depth is lake ice formed by freezing of subglacial Lake Vostok waters. This is indicated by the isotopic properties (δD, δ18O and deuterium excess), by electrical conductivity measurements (ECM), crystallography and gas content of the ice. These ice core data together with data on ionic chemistry favour an origin of the lake ice by frazil ice generation in a supercooled (below pressure melting point) water plume existing in the lake followed by accretion and consolidation by subsequent freezing of the host water.The helium profile of this deepest part of the Vostok core is quite unusual and surprising. It has important implications for the interactions between the ice sheet and the lake. Two constrasting scenarios can be satisfactorily constructed so that the lake residence time is not well constrained.  相似文献   

15.
黄河三角洲冰携泥现象及其产出的冰成沉积构造   总被引:1,自引:1,他引:1       下载免费PDF全文
通过野外实地考察、实验模拟,在黄河三角洲发现了一种非常特殊的、冰-(水-)泥共同作用而形成的冰携泥现象。冬末春初,冰雪融化,位于冰层底部的细粒碎屑沉积物质(粉砂或粘土)常被冰向上携起。研究认为,冰携泥的发育过程可以分为三个阶段:沉积物的破碎、冰层底部融化-泥沙被冰垂向搬运及泥沙下落-冰成球粒等的形成。在冰携泥的整个过程中可产出冰劈裂缝、冰成球粒和冰成泥沙片等特殊的沉积现象(构造),它们是冰携泥现象留下的重要的地质记录,对于恢复这一特殊现象及其形成的环境条件具有重要的指示意义。另外,初步探讨了冰携泥现象形成的两种可能机制:毛细作用和冰融水对流作用,并认为在冰融水能及时渗漏或排出的开放系统中,只有毛细作用机制发生作用;在冰融水不能被渗漏或排出的密闭系统中,两种机制共同发生作用。  相似文献   

16.
冻土过程参数化方案与中尺度大气模式的耦合   总被引:12,自引:5,他引:7  
将发展的冻土过程参数化方案与耦合了NCARLSM陆面过程模式的中尺度大气模式MM5相耦合,对包括我国北方,蒙古国,东西伯利亚的高纬度地区进行了模拟.模拟时间选为北半球季节冻土生成的10月份.模拟结果表明,模式能够较好地模拟出该区域的冻土分布,并且对大气模式中海平面气压场、气温场的模拟改进显著.  相似文献   

17.
Rock glaciers are distinct landforms whose wide distribution, occurrence, and significance often go unrecognised. They are deposits of poorly sorted, angular, blocky to tabular debris which are held together by an ice core or a matrix of ice-cemented fine clastics. Rock glaciers have formed in glaciated and non-glaciated areas. Many researchers have suggested that the absence of an ice core or the lack of movement indicates relict or fossil status. Active and inactive states can be viewed as the end members of a movement continuum. Movement rates, derived from world-wide locations as reported in the literature, range from less than 1 cmyr?1 to greater than 130cmyr?1. Unfortunately, lack of observed movement has been equated incorrectly with an inactive status. Rock glacier movement must be considered from a rheological point of view. Movement is controlled by the transformation of potential energy to kinetic energy as the system attempts to reach thermal equilibrium or stability. Whereas a glacier can completely disappear or redevelop, reactivation of a rock glacier requires only the re-establishment of the conditions responsible for development and maintenance of interstitial ice. Although it might not be possible to re-establish an ice core, interstitial areas can definitely be recharged with ice and thus facilitate movement. The concept of active versus inactive should be abandoned in favor of the view that a spatial and temporal continuum of form and movement exists.  相似文献   

18.
宋波  牛立超  黄帅  齐福强 《岩土力学》2014,35(Z1):285-291
地震作用下冰水域桥墩受到动水压力与动冰荷载的的双重影响。基于Morison动水理论和Croteau动冰力模型,提出一种适用于冰水域桥墩动力时程反应分析的简便计算模型,通过振动台试验验证了其有效性,并分析了海冰质量和水深对冰海域桥墩动力响应的影响。结果表明,强震作用下有冰时墩底最大曲率比无冰时最大增加8.93倍,桥墩被自由冰包围时,墩底截面出现最大曲率时对应的海冰质量随着水深的增加而变大;随着冰质量的持续增大,墩身最大位移易超越极限位移,造成桥梁垮塌,在桥梁设计中应重点考虑。  相似文献   

19.
东天山庙儿沟平顶冰川钻孔温度分布特征   总被引:5,自引:0,他引:5  
2005年8月在庙儿沟平顶冰川顶部海拔4 518 m处钻取了两根透底冰芯,对其中60 m的Core1冰芯钻孔利用热敏电阻温度计进行了温度测量,初步揭示了该处冰川的温度分布特征.结果显示,最低冰层温度-8.27℃出现在50 m深度处,这个深度在同类冰川中处于较低的位置;冰床底部的温度为-8.16℃,远低于压力融点.庙儿沟平顶冰川冰温的上述分布特征是在各种因素的影响下形成的,具有其独特性.这种温度分布特征,对冰芯记录过程较为有利,为恢复该地区气候与环境记录的准确性提供了保证.  相似文献   

20.
Antarctic sea ice cover plays an important role in shaping the earth’s climate, primarily by insulating the ocean from the atmosphere and increasing the surface albedo. The convective processes accompanied with the sea ice formation result bottom water formation. The cold and dense bottom water moves towards the equator along the ocean basins and takes part in the global thermohaline circulation. Sea ice edge is a potential indicator of climate change. Additionally, fishing and commercial shipping activities as well as military submarine operations in the polar seas need reliable ice edge information. However, as the sea ice edge is unstable in time, the temporal validity of the estimated ice edge is often shorter than the time required to transfer the information to the operational user. Hence, an accurate sea ice edge prediction as well as determination is crucial for fine-scale geophysical modeling and for near-real-time operations. In this study, active contour modelling (known as Snake model) and non-rigid motion estimation techniques have been used for predicting the sea ice edge (SIE) in the Antarctic. For this purpose the SIE has been detected from sea ice concentration derived using special sensor microwave imager (SSM/I) observations. The 15% sea ice concentration pixels are being taken as the edge pixel between ice and water. The external force, gradient vector flow (GVF), of SIE for total the Antarctic region is parameterised for daily as well as weekly data set. The SIE is predicted at certain points using a statistical technique. These predicted points have been used to constitute a SIE using artificial intelligence technique, the gradient vector flow (GVF). The predicted edge has been validated with that of SSM/I. It is found that all the major curvatures have been captured by the predicated edge and it is in good agreement with that of the SSM/I observation.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号