微震仪有线传输避雷研究

本文通过对雷电放电分析,研究解决微震仪有线传输的避雷问题,并介绍接收雷电信号控制传输线上电荷对地短路的“ＤＢＬ－１”避雷仪。     

Sedimentary Features of Shallow Ancient River Channels on the Northern Shelf of the South China Sea

Quaternary buried ancient river channels are widespread in the shallow-level sediments of the northern shelf of the South China Sea. The sedimentary sequence mainly of fluvial deposits comprise an important component part of the low-stand system tract and transgressive system tract in the study region. The plannar variation and spatial association of the sedimentary features such as incised valley fillings, deltaic foreset wedges and block slides of shelf-marginal fans reflect the palaeogeographic environment during the fall of the regional sea level in the northern part of the South China Sea. Based on the high-resolution seismic reflection data and gelogical data from boreholes, the present paper makes an integrated interpretation of the Quaternary ancient river channels in the shallow sediments of the study area, studies the sedimentary features of the ancient channels such as their spatial distribution, seismic facies reflection indicators, sedimentary facies and sand -body types, and discusses thei     

High-resolution photography of the solar chromosphere

A method is described for reconstructing the true geometry of a solar loop observed on the disk which takes account of tilt in its own plane. Reconstructions of three H loops yield small tilt angles (14°) and provide further evidence that H loops show a close correspondence to the field lines of a magnetic dipole. The method offers new opportunities for exploring the physics of individual solar loops.     

Dynamical interpretation of observed plasmasphere deformations

Based on all of the OGO-5 light ion density measurements (covering the period from March, 1968 to May, 1969), a definition of “isolated plasma regions” was employed to locate the most prominent patches of enhanced light ion densities in the midst of the depleted region, outside of the main plasmasphere. On the dayside, the distribution of these isolated plasma in L.T. vs. L coordinates was quite similar to that of the “detached plasma regions” by Chappell (1974a). On the nightside, however, the new distribution revealed more frequent occurrence of these regions. Elongated thick plasmatails produced during periods of sudden enhancement of convection electric fields and subsequentially thinning and corotating of the plasmatails during quieting periods, in general, could account for the statistical distribution as well as the individual events, such as those between March 27 and April 2, 1968 and Oct. 21 and Oct. 24, 1968. As demonstrated by Kivelson (1976), wave-particle interactions could produce tremendously complicated structures observed in the near vicinity of the plasmapause and far away from the plasmasphere. Examination of H⁺ and He⁺ density measurements for period of Aug. 12–Aug. 20, 1968 indicated that the density reduction of the plasmasphere during a magnetic storm was on the same order of magnitude as that obtained from whistler techniques during a magnetospheric substorm.     

Traction image method for irregular free surface boundaries in finite difference seismic wave simulation

In this study, we propose a new numerical method, named as Traction Image method, to accurately and efficiently implement the traction-free boundary conditions in finite difference simulation in the presence of surface topography. In this algorithm, the computational domain is discretized by boundary-conforming grids, in which the irregular surface is transformed into a 'flat' surface in computational space. Thus, the artefact of staircase approximation to arbitrarily irregular surface can be avoided. Such boundary-conforming gridding is equivalent to a curvilinear coordinate system, in which the first-order partial differential velocity-stress equations are numerically updated by an optimized high-order non-staggered finite difference scheme, that is, DRP/opt MacCormack scheme. To satisfy the free surface boundary conditions, we extend the Stress Image method for planar surface to Traction Image method for arbitrarily irregular surface by antisymmetrically setting the values of normal traction on the grid points above the free surface. This Traction Image method can be efficiently implemented. To validate this new method, we perform numerical tests to several complex models by comparing our results with those computed by other independent accurate methods. Although some of the testing examples have extremely sloped topography, all tested results show an excellent agreement between our results and those from the reference solutions, confirming the validity of our method for modelling seismic waves in the heterogeneous media with arbitrary shape topography. Numerical tests also demonstrate the efficiency of this method. We find about 10 grid points per shortest wavelength is enough to maintain the global accuracy of the simulation. Although the current study is for 2-D P-SV problem, it can be easily extended to 3-D problem.     

福建省大田县广平含煤区推覆构造特征及找煤预测

通过对区内推覆构造及地层等的研究，认为广平含煤区推覆体下蕴藏着丰富的煤炭资源，童子岩组煤系地层埋藏深度主要受发育于童子岩组上部的F1、F2推覆断层控制，并圈定出煤炭资源预测前景较好的3个区作为煤炭勘查后备基地。     

中国岩溶洞穴数据库建设研究

为了有效地保护和利用洞穴这一具有多方面价值的、不可再生的国土资源而建立了中 国岩溶洞穴数据库,首期完成900个洞穴数据建库工作。数据库中含有图、文、声、 像等方面的数字化信息,数据容量2500MB,作为非商业数据,可通过授权共享,为 科研机构、旅游行业和公众提供服务。     

不放过对每一块土地的监管——在“国土资源信息化建设研讨会”上的报告

尊敬的鹿部长,各位嘉宾,各位代表,大家好!孔子式负版者,自古圣贤都对从事国土资源管理工作,顶礼膜拜,今天参加大会的代表,都是信息时代国家和地方负责土地资源的领导:都是从事国土资源信息化、现代化的精英,请允许我向各位代表,各参展单位和参加研讨会的同志们,表示崇高的敬意!并祝贺大会圆满成功,我国国土资源管理与信息化事业,与时俱进,兴旺发达。     

Practical Research of IKONOS-2 Geopositioning and Its Accuracy in Tibet of China

This paper presents the studies of the refining of IKONOS-2 RPC, the transform of the datum, the mode of the control point distribution and the method of IKONOS stereo triangulation, so that IKONOS imagery can be used to collect the precise geospatial data and produce the large scale map. The transform between the IKONOS-2 image space and the national coordinate system based on the RPC have been developed, and the results of block adjustment with various control schemes in a practical project near Himalayas have been examined and analysed. The encouraging results of high positioning accuracy have been obtained.