岩溶含水介质渗透性空间结构分析的模型及其应用

岩溶含水介质渗透性的空间分布具有随机性与结构性的双重性质,本文探讨了运用区域化变量理论研究岩溶含水介质渗透性空间结构特征的数学模型及多数的物理意义,并阐述了具体的应用方法。为了综合表征岩溶含水介质渗透性的空间变异特点,给出了方向综合变异指标Ｄｖ。      

Prediction of tropical cyclone frequency with a wavelet neural network model incorporating natural orthogonal expansion and combined weights

A nonlinear wavelet neural network (WNN) model with natural orthogonal expansion (NOE) and combined weights is constructed to predict the annual frequency of tropical cyclones (TCF) occurring over the coastal regions of Southern China. Combined weights are obtained by calculating categorical weights, based on the particle swarm projection pursuit, and ranking weights, based on fuzzy mathematics, followed by optimization. The global monthly mean heights at 500?hPa and sea-surface temperature fields are used as two predictors. The linear and nonlinear information of the predictors with reduced dimensions is gathered through the NOE and combined weights, respectively, and treated as the input into the WNN model. This model is first trained with the 55-year (i.e., 1950?C2004) TCF data and then used to predict annual TCFs for the subsequent 5?years (i.e., 2005?C2009). Results show that the mean absolute and relative errors are 0.6175 and 9.34?%, respectively. The impacts of the combined weights, NOE and WNN as well as the traditional multi-regression approach on the TCF prediction are examined. Results show superior performance of the WNN-based model in the annual TCF prediction.     

A quantitative assessment on groundwater salinization in the Tarim River lower reaches, Northwest China

Based on monitored data from 840 samples, we assessed the spatial and temporal variability of groundwater salinization in the Tarim River lower reaches combining classical statistics and geostatistics. Results show that total dissolved solids （TDS） is significantly correlated with other related ions, such as Na＋, Mg2＋, Ca2-, C1- and K＋. TDS and underground water level have characteristics of spatial autocorrelation, both of which present the isotropic characteristic and con- form to the spherical model in each year from 2001-2009. TDS is basically greater than 1 g/L but less than 2 g/L in the Tarim River lower reaches, which indicates that salt stagnation pollution is more serious. The most serious salinization （3 g/L 〈 TDS _〈 35 g/L） contaminated area is mainly in the middle and lower part of the study area.     

太行山区龙华河群的建立与否定

太行山北段早前寒武系龙华河群为六十年代所建,后来发现五台山区的五台群底界已延入龙华河群之中。近年来,许多新资料表明,它实际上包括了龙泉关群、五台群及滹沱群的一部分。因而,应废除龙华河群,并对它进行重新划分。     

重力式挡土墙抗滑稳定分析安全判据和标准

探讨水利、交通等领域挡土墙设计规范中对抗滑稳定安全系数规定的允许值的合理性,认为其相应值与国外相关规定相比偏小。从理论上分析,使用抗力除以土压力的安全系数定义计算土压力相应的强度参数是标准值,而非经分项系数或安全系数折减后的标准值,其允许安全系数宜大于边坡等同类土方构筑物的相应值。认为建立在可靠度理论指导下的分项系数方法可以从根本上摆脱在安全判据方面存在的缺陷。在假定一级建筑物的允许可靠指标为3.7、土的黏聚力和摩擦系数变异系数分别为0.2和0.1的条件下,对一个特定的算例,填土的黏聚力、摩擦系数和基底的摩擦系数分项系数标定值分别为 1.301, 1.209和 1.170,应用提出的相对安全率判据,可以发现上述的分项系数标定值具有普适意义。该成果可以为相关规范的制订提供参考。     

Triassic alkaline intrusives in the Yanliao-Yinshan area: their chronology, Sr, Nd and Pb isotopic characteristics and their implication

Dated isotopic ages for 15 alkaline intrusives in the Yanliao-Yinshan area, ranging from 268 to 190 Ma, ten of which are from 250 to 208 Ma, indicate that most of them were formed in the Triassic Epoch. All the E_Nd(t) ratios from - 17.19 to -3.21 averaging -7.09, the E_Sr(t) ratios fmm 11.7 to71.5 averaging 36.63, and the I_sr(t) ratios from 0.705 0 to 0.709 3 averaging 0.706 8, show their characteristics of enrichment. On the E_Nd (t) virus E_Sr(t) correlation diagram, the samples from these intmsives were plotted within the enriched mantle trend lines and just outside, demonstrating their close connection to materials from the enriched mantle reservoir, taking into account the same Pb isotopic composition as that of the mantle.     

地球油气资源潜力是自然科学的基本问题

层序地层学自１９８７年问世以来，在国外如火如荼地发展起来，石油地质界对它的发展尤为关注。然而，在我国却显得举步维艰，进展缓慢。本文讨论了出现这种状况的起因：①不认识地震反射界面基本上是等时面；②认为地震／层序地层学是研究被动大陆边缘海相地层产生的，不适于非海相地层；③常规剖面中的地震反射频率和分辨率太低，不足以进行层序地层学研究；④层序地层学属纯理论科学，脱离油气勘探实际，采纳它的概念可能打气生产秩序。最后文章从正面阐述了开展层序地层学研究的必要性。     

The impact of climate change on runoff in the Yarlung Tsangpo River basin in the Tibetan Plateau

The Tibetan Plateau (TP) is the “water tower of Asia” and it plays a key role on both hydrology and climate for southern and eastern Asia. It is critical to explore the impact of climate change on runoff for better water resources management in the TP. However, few studies pay attention to the runoff response to climate change in large river systems on the TP, especially in data-sparse upstream area. To complement the current body of work, this study uses two rainfall-runoff models (SIMHYD and GR4J) to simulate the monthly and annual runoff in the upstream catchments of the Yarlung Tsangpo River basin (YTR) under historical (1962–2002) and future (2046–2065 A1B scenario) climate conditions. The future climate series are downscaled from a global climate model (MIROC3.2_hires) by a high resolution regional climate model (RegCM3). The two rainfall-runoff models successfully simulate the historical runoff for the eight catchments in the YTR basin, with median monthly runoff Nash–Sutcliffe Efficiency of 0.86 for SIMHYD and 0.83 for GR4J. The mean annual future temperature in eight catchments show significant increase with the median of +3.8 °C. However, the mean annual future precipitation shows decrease with the median of ?5.8 % except in Lhatse (+2.0 %). The two models show similar modeling results that the mean annual future runoff in most of catchments (seven in eight) shows decrease with the median of ?13.9 % from SIMHYD and ?15.2 % from GR4J. The results achieved in this study are not only helpful for local water resources management, but also for future water utilization planning in the lower reaches region of the Brahmaputra.     

均质土坡的安全系数

本文用变分法的基本理论的方法，推导出了均质土坡稳定性在平面应变情况下的基本方程，将简单边坡无粘性土（Ｃ＝０）与纯粘性土ψ＝０）的情况作为特例导出了相应的计算方法与计算公式，并对传统的条分法与土坡临界高度计算方法进行了讨论。