淹没丁坝群水力计算的试验研究

通过三姓浅滩定床物理模型试验,对淹没丁坝群的有关水力计算及对水位影响进行了试验研究,并提出了一种淹没丁坝群水面线计算的虚糙率方法.该方法简便实用,经实测资料验证,吻合较好.     

Unravelling the spirals: a serial thin-section study and three-dimensional computer-aided reconstruction of spiral-shaped inclusion trails in garnet porphyroblasts

Abstract Seventy-seven spatially orientated, serial thin sections cut from a single rock reveal changes in the geometry of spiral-shaped inclusion trails (SSITs) in garnet porphyroblasts. The observed SSITs are doubly curved, non-cylindrical surfaces, with total inclusion-trail curvature decreasing systematically from the cores to the rims of porphyroblasts. The three-dimensional geometry of the SSITs, reconstructed with the aid of computer graphics, shows that the orientations of spiral axes defined by the SSITs are not related in any expected nor predictable way to the main foliation in the matrix. This suggests continued deformation after or during the latest stages of porphyroblast growth, which has important implications for the use of SSITs as shear-sense indicators. Whether the formation of SSITs involves significant porphyroblast rotation with respect to a geographically fixed reference frame cannot be determined from the available data.     

A statistical analysis of exploration geochemical data for uranium

This paper describes a statistical analysis of reconnaissance exploration geochemical data for uranium. Three sets of data were analyzed, as they related to: (a) Charlotte-Winston-Salem and (b) Charlotte two-degree NTMS quadrangles of the south-eastern U.S.A. The coefficient of variation for uranium in each of the three sets of data was less than unity and hence no transformation of the original variable was needed. These data were subjected to correlogram analysis. A first-order Markovian model of the type: Y₀ exp (-a |p|) was fit by the least-squares method to serial correlation coefficients of these data using the method proposed by Deming (1948). The model was tested by computing the variance-volume relationship for assumed individual blocks of unit length. The noise in the input (record) was eliminated by the application of an optimum bilateral exponential smoothing technique developed by Agterberg. A comparison of spectral density estimates obtained by a maximum entropy method employing Yule-Walker equations and the Burg algorithm was also made. The prediction error coefficients needed to determine the order of the autoregressive process and hence the spectral densities were determined in both cases for the three sets of data.On leave from National Geophysical Research Institute, Hyderabad-7, India.     

可视化XRF软件数据采集系统的开发

介绍了在Windows操作系统下用VC^ 6．0编制的XRF分析软件。该软件采用基于多线程的串口数据采集及处理技术，且操作方便数据处理能力强。     

Seismic behaviour of cracked concrete gravity dams

A finite element model of incremental displacement constraint equations (IDCE), based on an existing node‐to‐surface concept, is implemented to deal with dynamic contact surfaces in the seismic behaviour analysis of cracked concrete gravity dams. After verification for sliding, rocking and impact, the IDCE model is applied to study the seismic responses of concrete gravity dams with different profiles and crack locations for a variety of parameters, such as coefficient of friction, water level and type of earthquake, as well as impact damping based on the concept of coefficient of restitution. It is revealed that cracked concrete gravity dams can experience not only sliding and rocking modes, but also the drifting mode in some cases of crack either at the base or at a height. Downstream sliding is normally accompanied by rocking, especially for the cases of crack at a height. Due to rocking and drifting, a cracked dam may still acquire a certain amount of residual sliding even if the effective coefficient of friction is relatively high. Copyright © 2005 John Wiley & Sons, Ltd.     

De-bugging the 'millipede' porphyroblast microstructure: a serial thin-section study and 3-D computer animation

ABSTRACT Seventy-five spatially orientated, serial thin sections cut from a single rock containing ‘millipede’ porphyroblast microstructure from the Robertson River Metamorphics, Australia, reveal the three-dimensional (3-D) geometry of oppositely concave microfolds (OCMs) that define the microstructure. Electronic animations showing progressive serial sections of the 3-D microstructure are made available via the World Wide Web. The OCM amplitudes decrease regularly from a maximum in near-central sections to a minimum in near-marginal sections, whereas the OCM interlimb angles increase regularly from a minimum in near-central sections to a maximum in near-marginal sections. These observations illustrate that the OCMs are noncylindrical surfaces with culminations located in near-central sections. Because the porphyroblast cores appear to have been present before significant development of the syn-OCM foliation, all of the OCMs were formed by heterogeneous extension around these cores. The overall geometry of the OCMs described here reflects the strain state, and cannot be used to constrain deformation paths.     

用TURBO BASIC实现国际二号码的异步串行通信

着重介绍了国际二号码与ASCII码相互转换及用TURBOBASIC实现异步串行通信时的一些关键技术的解决办法。     

Channel erosion along the Carmel river,Monterey county,California

Historic maps, photographs, and channel cross-sections show that the channel of the Carmel River underwent massive bank erosion, channel migration, and aggradation in a major flood in 1911, then narrowed and incised by 1939. The channel was stable until 1978 and 1980, when bank erosion affected some reaches but not others. The narrowing and incision were in response to a lack of major floods after 1914 and construction in 1921 of a dam that cut off sediment supply from the most actively eroding half of the basin. Localized erosion in 1978 and 1980 occurred during low magnitude events along reaches whose bank strength had been reduced by devegetation. These events illustrate that the stability of a fluvial system can be disrupted either by application of a large erosive force in a high magnitude event (the 1911 flood) or in a low magnitude event, by reducing the resistance to erosion (bank devegetation). The Carmel River is a potentially unstable system. Its discharge and slope characteristics place it near the threshold between meandering and braided. On the Lower Carmel, the presence of bank vegetation can make the difference between a narrow, stable meandering channel and a wide shifting channel with braided reaches.     

尾矿坝治理技术

尾矿坝在矿山环境的保护和治理中起到很大的作用，它主要应用于堆放和处理矿山生产所带来的废渣、废水等污染物质，而坝体浸润线过高会影响尾矿坝的稳定性。尾矿坝治理技术众多，重点介绍了管井法降水、垂直水平自流排渗法、水平自流排渗法、辐射井排渗法等。在结合实例讨论的基础上，综合分析了不同方法的优、缺点，并提出了其应用范围以及其在应用中应注意的技术问题。