抽油机悬点投影测量仪     

文志雄  戚克军  李明  曾南志 《大地测量与地球动力学》2002,22(1):110-113

油田抽油机的抽油杆幌动幅度过大，是引起抽油杆断裂的一个重要因素，检测这种幌动幅度是防止抽油杆断裂的一种有效手段。设计了一种基于面阵CCD和普通半导体激光器（LD）测量这种幌动的悬点投影测量方法，通过数字卷积滤波，达到了范围为0－40mm，误差＜0.2mm的技术检测指标。  相似文献   

太阳发电机理论研究进展     

姜杰  汪景琇 《天文学进展》2005,23(2):121-134

太阳发电机理论主要解释太阳磁场的起源和演化，是太阳物理中最基本、最重要的问题之一．对它的研究不仅具有重要的科学价值，而且对空间天气的预测和空间技术的发展有一定的影响．随着日震学的发展，该理论也得到了很大改进。从相关观测入手，综述了发电机理论需解释的观测事实，以及为发电机理论提供约束的太阳内部动力学结构；介绍了基本理论和近来的主流模型，并指出尚待解决的问题和进一步的努力方向。  相似文献   

中国1∶100万景观生态制图设计   总被引：5，自引：0，他引：5  

程维明  柴慧霞龙恩  刘海江张旸 《地球信息科学学报》2004,6(4):19-24

中国1∶100万景观生态图系借鉴国内外传统景观制图方法和制图规范,在遥感、地理信息系统先进技术的支持下,设计研制其制图方法、制图内容、样图和技术流程,同时提出初步的景观分类系统,为今后编制中国1∶100万景观生态图奠定基础。  相似文献   

Application of micropolar plasticity to post failure analysis in geomechanics     

Majid T. Manzari 《国际地质力学数值与分析法杂志》2004,28(10):1011-1032

A micropolar elastoplastic model for soils is formulated and a series of finite element analyses are employed to demonstrate the use of a micropolar continuum in overcoming the numerical difficulties encountered in application of finite element method in standard Cauchy–Boltzmann continuum. Three examples of failure analysis involving a deep excavation, shallow foundation, and a retaining wall are presented. In all these cases, it is observed that the length scale introduced in the polar continuum regularizes the incremental boundary value problem and allows the numerical simulation to be continued until a clear collapse mechanism is achieved. The issue of grain size effect is also discussed. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

A synthesis map of the sky at 34.5 MHz     

K. S. Dwarakanath  N. Udaya Shankar 《Journal of Astrophysics and Astronomy》1990,11(3):323-410

This paper describes a wide-field survey made at 34.5 MHz using GEETEE,1 the low frequency telescope at Gauribidanur (latitude 13°36′12′′N). This telescope was used in the transit mode and by per forming 1-D synthesis along the north-south direction the entire observable sky was mapped in a single day. This minimized the problems that hinder wide-field low-frequency mapping. This survey covers the declination range of-50° to + 70° (- 33° to +61° without aliasing) and the complete 24 hours of right ascension. The synthesized beam has a resolution of 26′ x 42′ sec (δ- 14°. 1). The sensitivity of the survey is 5 Jy/beam (1σ). Special care has been taken to ensure that the antenna responds to all angular scale structures and is suitable for studies of both point sources and extended objects This telescope is jointly operated by the Indian Institute of Astrophysics, Bangalore and the Roman Research Institute, Bangalore.  相似文献   

AN EVALUATION OF SAS/GRAPH SOFTWARE FOR COMPUTER CARTOGRAPHY1     

Alan M. Baker  Rowan Faludi  David R. Green 《The Professional geographer》1985,37(2):204-214

The SAS® computer software system, widely used and respected for its capabilities in statistical analysis and data base management, now includes a new set of graphic and cartographic procedures called SAS GRAPH?. We have used these cartographic procedures in research on mapping ethno-cultural census data from metropolitan areas in Ontario and in undergraduate and graduate courses in computer cartography. On the basis of that experience, we describe and evaluate SAS/GRAPH'S cartographic capabilities and illustrate with maps drawn by various devices.  相似文献   

对"数字地球"的几点认识   总被引：7，自引：0，他引：7  

江绵康 《地理信息世界》2003,1(3):1-3,13

自“数字地球”的概念被提出以来，已引起全球的广泛关注和积极响应。然而，数字地球在目前还仅仅是一个概念。为了逐步建立“数字地球”，需要就“数字地球”的理论、技术以及实现进行深入地探讨。从“数字地球”的产生背景、基本概念、研究内容、构成框架、关键技术、实施难点和发展战略等方面谈了对“数字地球”的一些认识。  相似文献   

昆仑山口大地震与地形变异常的讨论   总被引：7，自引：5，他引：2  

薄万举  张祖胜  郭良迁 《大地测量与地球动力学》2003,23(1):22-28

针对昆仑山口大地震，总结了多种地形变（大地测量）手段所显示的异常变化及其时空分布，结果显示：8．1级大震前存在空间尺度大，时间尺度的地形变前兆异常，简要介绍了相关的异常图像，给出了初步解释，并对未来震情的发展进行了探讨，认为近期内强震活动向华北迁移的可能性不大。  相似文献   

A qualitative and quantitative evaluation of experimental model catchment evolution     

G. R. Hancock  G. R. Willgoose 《水文研究》2003,17(12):2347-2363

Due to the geological time scales required for observation of catchment evolution, surrogates or analogues of field data are necessary to understand long‐term processes. To investigate long‐term catchment behaviour, two experimental model catchments that developed without rigid boundaries under controlled conditions are examined and a qualitative and quantitative analysis of their evolution is presented. Qualitatively, the experimental catchments have the visual appearance of field scale data. Observation demonstrates that changes in catchment shape and network form are conservative. Quantitative analysis suggests that the catchments reach an equilibrium form while a reduction in the channel network occurs. While the catchments are laboratory scale models, the results provide insights into field scale behaviour. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

形变大地测量学的进展、问题与地震预报   总被引：12，自引：7，他引：5  

周硕愚  吴云  李正媛  杜瑞林 《大地测量与地球动力学》2004,24(4):95-101

简要概括了形变大地测量学的革命性进展，研讨了它的科学特色、功能和定义以及对地球科学和防灾减灾的推动。形变大地测量学有助于从根本上击破多年来制约地震预报的“瓶颈”，但也存在不少急待解决的问题。着重研讨了在21世纪前10年，形变大地测量学如何依托多年的学科积累并充分受益于人造卫星和数字化等新技术，开展创新性研究和试验以推进地震预报。为此，对当前的研究工作提出了12条科学技术途径。最后对学科名称提出了建议。  相似文献