DW—10型电涡流传感器的性能测试     

朱虎 《地震地磁观测与研究》1993,14(6):7-10

介绍了DW-10型电涡流位移传感器的主要技术性能及测试结果。其灵敏度为11-13mV/μm;线性范围达±0.5mm;线性度≥0.8％传感器对被测体的作用力<1×10~(-9)N。  相似文献   

Temperature dependence of the magnetic rotation process of kaolinite microcrystals containing paramagnetic impurity ions dispersed in liquid medium     

C.?UyedaEmail author  M.?Sakakibara  K.?Tanaka 《Physics and Chemistry of Minerals》2003,30(7):425-429

Temperature dependencies of magnetic rotation were measured in micron-sized silicates dispersed in ethanol for two different samples of kaolinite. Magnetic rotation proceeded by balance between thermal agitation energy and magnetic anisotropy energy. Measurements were performed between 195 and 343 K. The field intensity required to achieve magnetic alignment of microcrystals increases with temperature, because of the temperature dependence of paramagnetic anisotropy, and the temperature dependence of thermal agitation energy. The results indicate that the values of magnetic anisotropy of nonmagnetic materials might partially derive from the paramagnetic moments, which derive from paramagnetic impurity ions. The present experiment provides a technical basis for determining the precise values of diamagnetic anisotropy ()_DIA from minerals which have a concentration of paramagnetic ions and do not form a single crystal large enough to allow bulk measurements. The values of ()_DIA can be obtained by extrapolating the –T relations, which follow the Curie law, to the temperature limits.  相似文献   

网络化智能传感器及其即插即用接口设计   总被引：9，自引：0，他引：9  

吴仲城  卞亦文  汪增福 《武汉大学学报(信息科学版)》2003,28(2):242-247

针对网络环境下的信息获取,提出了采用网络化智能传感器的设计思想,以实现传感器的即插即用功能。围绕传感器在线辨识、参数修正,采用电子数据表单(TEDS)方式对传感器的生产厂家、日期、校准参数等传感器特征属性进行描述,并给出传感器网络化的拓扑结构、校准模型和数字接口(包括软、硬件)的实现方法。  相似文献   

长珲高速公路某边坡锚索受力分析及选型          下载免费PDF全文

刘士虎  卢文阁  于万富  徐志超 《探矿工程》2005,32(8):32-34

压力分散型锚索以其合理的受力机理及其在软弱土体中能更有效地发挥土体承载能力的优势取得了在本工程中的优选。主要介绍了该类型锚索的特点、作用机理和张拉程序，同时对工程的施工情况作了简述。  相似文献   

RTK技术在东边道铁路定测中的应用   总被引：1，自引：0，他引：1  

李旷建  王占华  李玉玲 《全球定位系统》2006,31(4):29-32

通过对RTK技术在东边道铁路线路测量中的应用和探讨，并通过对RTK施放控制桩点后再经静态观测的解算值和控制桩点设计值的比较，阐述了RTK技术的高精度及可靠性，为将RTK技术在铁路线路测量中更好地得以应用和推广有着重要的意义和参考价值。  相似文献   

感应法地下管线探测中的一个问题   总被引：2，自引：0，他引：2  

阮百尧 《物探与化探》1997,21(5):382-385,393

通过对地下管线中的感应电流形成机理分析,本文认为,当地下介质导电性很差时,地下管线以磁偶极线为主;而当地下介质存在一定的导电性时,管线则等效于电流线。  相似文献   

中国的特种精密工程测量   总被引：2，自引：1，他引：2  

吴翼麟 《测绘工程》1997,6(2):1-7

介绍大坝变形观测、波带板激光准直系统等特种精密工程测量方法，在工程与工业建设、大型建构筑物变形观测及抗灾减灾等方面取得的成就和效益；阐述特种精密工程测量的成长道路，以及当前特种精密工程测量的热门话题与发展趋势。  相似文献   

Structural Alignment Methods with Applications to Geospatial Ontologies     

Isabel F Cruz  William Sunna 《Transactions in GIS》2008,12(6):683-711

We consider the problem of enabling interoperability and information sharing among geospatial applications that use ontologies to describe their concepts and the relationships among them. We present two fully automatic alignment methods that use the graph structures of a pair of ontologies to establish their alignment, that is, the semantic correspondences between their concepts. We have tested our methods on geospatial ontologies pertaining to wetlands and four other pairs that belong to a repository that has been used in the Ontology Alignment Evaluation Initiative (OAEI). Using these ontologies, we have compared the effectiveness (precision and recall) of our methods against the Similarity Flooding Algorithm that was proposed by others and show that for each of the tested ontologies one of our methods is at least as effective as their method. We have tuned the performance of our methods by introducing a greedy approach that reduces the number of concepts that get compared. This approach reduces runtime by approximately 30% with a minor compromise to the effectiveness of the results. To further validate our approach, we participated in the OAEI competition to align a pair of ontologies, each with a few thousand concepts.  相似文献   

Modeling Magnetic Tower Jets in the Laboratory     

A. Ciardi  S. V. Lebedev  J. P. Chittenden  D. J. Ampleford  S. N. Bland  B. S. Bott  J. Rapley 《Astrophysics and Space Science》2005,298(1-2):277-286

The twisting of magnetic fields threading an accretion system can lead to the generation on axis of toroidal field loops. As the magnetic pressure increases, the toroidal field inflates, producing a flow. Collimation is due to a background corona, which radially confines this axially growing “magnetic tower”. We investigate the possibility of studying in the laboratory the dynamics, confinement and stability of magnetic tower jets. We present two-dimensional resistive magnetohydrodynamic simulations of radial arrays, which consist of two concentric electrodes connected radially by thin metallic wires. In the laboratory, a radial wire array is driven by a 1 MA current which produces a hot, low density background plasma. During the current discharge a low plasma beta (β < 1), magnetic cavity develops in the background plasma (β is the ratio of thermal to magnetic pressure). This laboratory magnetic tower is driven by the magnetic pressure of the toroidal field and it is surrounded by a shock envelope. On axis, a high density column is produced by the pinch effect. The background plasma has >rsim1, and in the radial direction the magnetic tower is confined mostly by the thermal pressure. In contrast, in the axial direction the pressure rapidly decays and an elongated, well collimated magnetic-jet develops. This is later disrupted by the development of m = 0 instabilities arising in the axial column.  相似文献   

Calibration and use of pressure transducers in soil hydrology     

J. F. Dowd  A. G. Williams 《水文研究》1989,3(1):43-49

Laboratory and field experiments demonstrated that solid state pressure transducers are accurate and reliable devices for frequent measurements of soil suction. However, each transducer had to be individually calibrated before use and a hanging column procedure designed for this purpose is described. Analysis showed that each transducer had a linear response and that environmental conditions such as temperature had minimal influence. Twenty four tensiometers with pressure transducers were intalled in a forest soil to test their operation and their output was monitored by a data logger. An example of soil suction results measured during four storms is given to demonstrate their stability and their rapid response. The transducers were found to perform accurately and were only affected by temperatures below 0°C.  相似文献