综合物探在鄱阳湖铁路特大桥勘察中的应用

鄱阳湖铁路特大桥桥址位于鄱阳湖入长江的交汇处。该区地质情况复杂,断裂构造十分发育,因此地质勘探对桥址方案的比选显得尤为重要。此次有效地利用了综合物探,采用多种方法查明了岩性分区和地质构造格局,取得了良好的地质效果。充分显示了综合勘探、综合物探的优势。     

从遥感影像提取道路特征的方法综述与展望

从遥感影像中提取道路特征已有许多研究,但仍存在许多问题有待解决。本文探讨了道路特征提取的基本思路,对道路特征提取的基本方法和现状进行了较全面的综述,介绍了具有代表性的特征提取方法,并对各个方法的特点进行了分析,最后对道路特征提取的研究前景进行了展望。     

鄱阳湖组(第四系)的修订及特征

根据对鄱阳湖地区 Zk0 1钻孔柱状剖面的研究 ,对鄱阳湖组的定义进行修订、补充 ,认为鄱阳湖组为一套以青灰色淤泥质粘土、黄褐色粘土、粉质粉土为主夹少量粉砂或细砂的湖泊—河口三角洲相沉积。年代地层为第四系全新统 ,底界年龄约 6 2 10± 12 5 a B.P.,开阔湖泊沉积始于 32 4 0± 180 a B.P.,且由北向南时代渐新 ,具有明显的穿时性     

某城地下水地表水联合优化调度管理模型实例

本文阐述了利用响应矩阵法建立地下水、地表水优化调度管理模型的约束条件、并用目标规划法进行管理模型计算的一个实例。这是一个位于黄河之滨的城市,市内有许多名泉。近年来大量开采地下水已使泉水干涸,而黄河水在某些月份含沙量很大,不宜全年开采。本计算求得了这个城市几个水源地与黄河水在一个枯水年(或丰水年)内各月份的优化开采量分配方案,使之既可保证泉水全年喷涌;叉可提供所需水量。     

Assessment of future climate change over East Asia due to the RCP scenarios downscaled by GRIMs-RMP

This study assesses future climate change over East Asia using the Global/Regional Integrated Model system—Regional Model Program (RMP). The RMP is forced by two types of future climate scenarios produced by the Hadley Center Global Environmental Model version 2 (HG2); the representative concentration pathways (RCP) 4.5 and 8.5 scenarios for the intergovernmental panel on climate change fifth assessment report (AR5). Analyses for the current (1980–2005) climate are performed to evaluate the RMP’s ability to reproduce precipitation and temperature. Two different future (2006–2050) simulations are compared with the current climatology to investigate the climatic change over East Asia centered in Korea. The RMP satisfactorily reproduces the observed seasonal mean and variation of precipitation and temperature. The spatial distribution of the simulated large-scale features and precipitation by the RMP is generally less reflective of current climatic conditions than that is given by the HG2, but their inter-annual variations in East Asia are better captured by the RMP. Furthermore, the RMP shows higher reproducibility of climate extremes including excessive heat wave and precipitation events over South Korea. In the future, strong warming is distinctly coupled with intensified monsoonal precipitation over East Asia. In particular, extreme weather conditions are increased and intensified over South Korea as follows: (1) The frequency of heat wave events with temperature greater than 30 °C is projected to increase by 131 and 111 % in the RCP 8.5 and 4.5 downscaling, relative to the current climate. (2) The RCP 8.5 downscaling shows the frequency and variability of heavy rainfall to increase by 24 and 31.5 %, respectively, while the statistics given by the RCP 4.5 downscaling are similar to those of the current climate.     

A complementary depiction of the interannual variation of atmospheric circulation associated with ENSO events: Research note

Abstract

A simple diagnostic scheme, which combines a low‐pass temporal filter (with an 18‐month cutoff time) with a regular empirical orthogonal function (EOF) analysis, is used to delineate the synchronous evolution of El Nino‐Southern Oscillation‐related (ENSO‐related) modes in various variables of the ocean‐atmosphere system. Based on the causal relation chain of diabatic heating, divergent circulation and rotational flow, the diagnostic scheme extracts ENSO modes from the following data sources: the Pacific sea surface temperature (SST), the past 14‐years (1979–1992) of data generated by the Global Data Assimilation System of the National Meteorological Center, and a 10‐year (1979–1988) general circulation model climate simulation made at the Goddard Laboratory for Atmospheres. The analysis reveals the following: (a) the eigencoefficient time series of the first eigenmodes of selected filtered variables, which explain about 40–50% of their total variance, synchronize with the filtered SST averaged over Area NINO‐3; (b) the spatial structures of the first eigenmodes resemble the ensemble departures associated with ENSO events of these variables from their long term means; and (c) the results show that the proposed scheme can be easily applied to isolate and illustrate the time evolution of ENSO modes which exist in the long term observational database as well as in climate simulations.     

引入分形校正单元的图像重建计算点迭代算法

本文在计算点图像重建离散化模型的代数迭代算法中,引入分形校正单元构造迭代校正逼近。本文选取Hilbert曲线的最小开口方向作为校正单元连成折线来覆盖投影射线,由校正单元构成的近似曲线具有自相似结构。Hilbert曲线对计算点的投影衰减贡献的几何、物理意义清楚明确。通过加密计算点,由基本校正单元表达的线积分更为逼近地近似投影射线的线积分。分形结构的自相似性可以充分用于迭代校正的计算,形成统一的计算模板,利用几何结构的对称性,加快计算速度、提高成像精度。这一方法可以推广到三维成像模型,内容丰富。     

Laboratory investigation and simulation of breakthrough curves in karst conduits with pools

A series of laboratory experiments are performed under various hydrological conditions to analyze the effect of pools in pipes on breakthrough curves (BTCs). The BTCs are generated after instantaneous injections of NaCl tracer solution. In order to test the feasibility of reproducing the BTCs and obtain transport parameters, three modeling approaches have been applied: the equilibrium model, the linear graphical method and the two-region nonequilibrium model. The investigation results show that pools induce tailing of the BTCs, and the shapes of BTCs depend on pool geometries and hydrological conditions. The simulations reveal that the two-region nonequilibrium model yields the best fits to experimental BTCs because the model can describe the transient storage in pools by the partition coefficient and the mass transfer coefficient. The model parameters indicate that pools produce high dispersion. The increased tailing occurs mainly because the partition coefficient decreases, as the number of pools increases. When comparing the tracer BTCs obtained using the two types of pools with the same size, the more appreciable BTC tails that occur for symmetrical pools likely result mainly from the less intense exchange between the water in the pools and the water in the pipe, because the partition coefficients for the two types of pools are virtually identical. Dispersivity values decrease as flow rates increase; however, the trend in dispersion is not clear. The reduced tailing is attributed to a decrease in immobile water with increasing flow rate. It provides evidence for hydrodynamically controlled tailing effects.     

载荷试验确定基床系数修正方法的讨论

Winkler地基模型是目前工程界应用最广的一种地基模型,但对其关键参数——基床系数k的确定,许多文献的表述并不一致。该文在大量试验资料的基础上,通过对该问题的深入研究,阐明了通过载荷试验确定基床系数修正方法的有关概念。对于砂性土地基,载荷板试验得出的基准基床系数仅需要进行基础大小修正,而对于粘性土地基,则需要进行基础大小和基础形状两项修正。     

山东苍峄铁矿带沟西-西官庄矿区地下水微量元素Fe~(3+)富集赋存规律

2010年以来,对研究区内水文地质背景及不同层位水质化学测试样品数据分析研究,重点阐述了微量元素Fe3+的富集与含水介质岩性、地下水的酸碱度、地层含水性和氧化还原环境的关系,认为地下水中Fe3+富集赋存的最有利的环境是变质岩类地层;碳酸盐岩和碎屑岩中水化学类型HCO3-Ca型水分布最广,碳酸盐岩的地下水中Fe3+平均含量最低;变质岩中硫酸型(包括复合型)的地下水中Fe3+的平均含量最高,对Fe3+的行为呈正相关关系。地下水中Fe3+含量赋存具以副井及其外围地区为中心高浓度分带性。