数字化射线照相技术对轻物质的判断     

韩裕生  罗娅  丁厚本  邵立康  廖南  朱平安 《CT理论与应用研究》2002,11(1):10-12

本文介绍了数字化射线照相技术对轻物质进行判断的方法。经实践证明，该方法是合理和有效的，可大大增强对轻物质的识别能力，是一种非常可行的识别技术。  相似文献   

Common-Reflection-Surface Stack for Converted Waves     

Bergler  Steffen  Duveneck  Eric  Höcht  German  Zhang  Yonghai  Hubral  Peter 《Studia Geophysica et Geodaetica》2002,46(2):165-175

The finite-offset (FO) common-reflection-surface (CRS) stack has been shown to be able to handle not only P-P or S-S but also arbitrarily converted reflections. It can provide different stack sections such as common-offset (CO), common-midpoint (CMP) and common-shot (CS) sections with significantly increased signal-to-noise ratio from the multi-coverage pre-stack seismic data in a data-driven way. It is our purpose in this paper to demonstrate the performance of the FO CRS stack on data involving converted waves in inhomogeneous layered media. In order to do this we apply the FO CRS stack for common-offset to a synthetic seismic data set involving P-P as well as P-S converted primary reflections. We show that the FO CRS stack yields convincing improvement of the image quality in the presence of noisy data and successfully extracts kinematic wavefield attributes useful for further analyses. The extracted emergence angle information is used to achieve a complete separation of the wavefield into its P-P and P-S wave components, given the FO CRS stacked horizontal and vertical component sections.  相似文献   

复杂介质结构中折射界面的哈格多恩原理波前成像   总被引：6，自引：4，他引：6       下载免费PDF全文

徐朝繁  张先康  朱金芳  段永红  田晓峰  潘纪顺 《地震地质》2002,24(4):542-548

在城市活断层探测中 ,浅层结构常常表现为强烈的非均匀性 ,界面横向强烈起伏 ,层内速度变化较大 ,传统的基于平界面均匀层模型的折射资料处理方法不能适用。研究开发能应用于复杂介质结构中折射资料处理的方法就显得十分必要。文中基于惠更斯原理 ,用波前扩张法对波场作正演计算 ,根据哈格多恩折射波前成像原理 ,在lecomte算法和Hole有限差分计算程序的基础上 ,开发出 1种复杂介质结构中折射资料的处理方法与软件 ,并用此方法处理了福州城市活断层折射探测试验中在义序完成的 2条折射剖面资料。结果表明 :探测区浅层为 3层结构 ,分别为盖层、强风化层和基岩。基岩顶界面的埋深约为 5 8～ 5 2m ,盖层P波速度变化较大  相似文献   

Surface vibration due to a sequence of high speed moving harmonic rectangular loads     

G. Lefeuve-Mesgouez  A. T. Peplow  D. Le Houdec 《Soil Dynamics and Earthquake Engineering》2002,22(6):692

The transmission of vibrations over the surface of the ground, due to high-speed moving, vertical harmonic rectangular loads, is investigated theoretically. The problem is three-dimensional and the interior of the ground is modelled as an elastic half-space or a multilayered ground. The transformed solutions are obtained using the Fourier transform on the space variable. A new damping model in the spatial wavenumber domain, presented in Lefeuve-Mesgouez et al. [J. Sound. Vibr. 231 (2000) 1289] is used. Numerical results for the displacements on the surface are presented for loads moving with speeds up to and beyond the Rayleigh wave speed of the half-space.  相似文献   

地球物理技术在我国考古和文物保护工作中的应用   总被引：3，自引：6，他引：3  

钟世航 《地球物理学进展》2002,17(3):498-506

20世纪80年代以来，我国考古及文物保护工作者和地球物理工作者越来越认识到地球物理技术在考古和方物保护方面可以发挥作用，在古幕探查、大型古建筑地下遗存现状、古遗迹断代等方面，地球物理技术都找到了发挥作用的机会，本文通过地球物理技术在云冈石窟、龙门石窟、克孜尔石窟、北京故宫紫禁城、嵩岳寺塔、古泗州城遗址、风阳明中都等的物理探查实例，以及查找古幕、古遗迹断代等方面的工作，介绍了我国在考古和文物保护领域应用地球物理技术的进展，并指出了物探在用于考古和文保时的特点和展望。  相似文献   

结合农业科技园建设观光农园的探讨——以潮州鹤陇山农业科技园与观光农园的规划设计为例   总被引：2，自引：0，他引：2  

徐君亮  江璐明 《热带地理》2002,22(3):236-240

广东省经济和旅游业发展位于全国榜首，人多地少全国最为突出，但乡村旅游建设相对滞后，文中通过潮州市郊鹤陇山农业科技园与观光农园规划设计，论述了发展高新技术农业是新世纪广东农业必由之路，提出结合农业科技园建设，叠加农业观光园，把生态农业建设与旅游文化结合起来，是广东乡村旅游发展的主要途径。  相似文献   

洪水演进三维模拟仿真系统可视化研究   总被引：14，自引：0，他引：14  

袁艳斌  袁晓辉  张勇传  刘吉平  侯国祥 《山地学报》2002,20(1):103-107

洪水演进仿真系统的研制，是实施“数字流域”工程的重要组成部分；结合洪水演进可视化目标的分析，基于Visual C 系统开发平台，融GIS技术和Opengl开发技术，采用三角形逼近、光滑处理和加入法向量以控制光照的方式，实现了流域地形及河床的三维可视化仿真；应用广度优先搜索算法确定了运动水体与流域河床形态的自适应与自相依的关系，使流域洪水演进模拟具有真实自然的可视化效果。所研制的系统雏形，可有效的模拟流域洪水的三维演进过程；  相似文献   

History and necessity: the evolution of soil conservation technology in a Jamaican farming system     

Rebecca J. Kent 《The Geographical journal》2002,168(1):48-56

The soil conservation campaigns that have been a prominent feature of Jamaican agricultural policy since the 1950s are frequently presented as having failed to ameliorate the problem of soil erosion in hillside agriculture. A case study of a small farming community in the Blue Mountains explores the development of the soil conservation practices currently employed by farmers. The use of trash barriers in carrot farming is described and the origins of this technology and its subsequent adaptation are considered. The study concludes that extension interventions and government policy have influenced the development of current soil conservation practices; practices which have their roots in indigenous techniques. Other factors such as the adaptation of trash barriers to suit local conditions and their importance in soil fertility management also play a role in their widespread use in the study area. The study demonstrates that to understand the process of technical change in farming communities, it is necessary to consider a range of factors, external and internal, technical and social, that have over time influenced farmers' decision making.  相似文献   

Religion and technology: refiguring place, space, identity and community   总被引：1，自引：0，他引：1  

Lily Kong 《Area》2002,33(4):404-413

This paper reviews the literature on the religion–technology nexus, drawing up a research agenda and offering preliminary empirical insights. First, I stress the need to explore the new politics of space as a consequence of technological development, emphasizing questions about the role of religion in effecting a form of religious (neo)imperialism, and uneven access to techno-religious spaces. Second, I highlight the need to examine the politics of identity and community, since cyberspace is not an isotropic surface. Third, I underscore the need to engage with questions about the poetics of religious community as social relations become mediated by technology. Finally, I focus on questions about the poetics of place, particularly the technological mediation of rituals.  相似文献   

信息化施工技术在保护某厂濒危烟囱中的应用     

张子清 《上海国土资源》2003,(2):59-62

通过地处上海某厂锅炉房濒危烟囱北侧仅5米处的实验楼基础施工，详尽介绍了施工过程中保护濒危烟囱的防护工程对策，以及采用信息化施工技术而取得的良好经济效益。  相似文献