区域采样法测定水中硫酸根离子的研究

在分散度不同的区域内进行区域采样用于水中硫酸根离子的测定，结果令人满意。应用此方法测定硫酸根离子的线性范围为２００．０～３０００ｍｇ／Ｌ；进样频率为１２０次／ｈ；相对标准偏差为１．７０％     

地质样品中微量金银的在线分离富集方法

提出用ＶＳ－Ⅱ型强碱性阴离子交换纤维定量富集、硫脲解脱，流动注射在线分离富集—火焰原子吸收光谱法测定地质样品中痕量金银的分析方法。该方法检出限低，金为１．４μｇ／ｍＬ，银为０．３５μｇ／ｍＬ，相对标准偏差均小于２％，采样频率为１２０次／ｈ，用于地质样品中痕量金银的直接测定，结果令人满意。     

福建及台湾海峡地震预警工程架构探索

福建及台湾海峡是海陆板块碰撞到板内地震活动过渡带 ,东侧毗邻台湾板缘地震带 ,西侧为福建内陆板内地震活动区。这是得天独厚的观测研究大陆边缘地震构造带强震活动及板块动力学的良好地域。当前 ,我国进入全面建设小康社会历史时期 ,为防御地震造成社会灾害 ,实现以人为本 ,防患于未然 ,势必需要建构一个实用化的地震预警工程及其机制。本文即是在对福建及台湾海峡近 30多年以来观测研究的基础上 ,提出应用现代空间技术、数字地震、计算机网络等技术架构地震预警工程与机制的一种设想。     

川藏公路二郎山隧道和平沟泥石流特征研究与治理设计

泥石流作为地质环境较差的山区的主要自然灾害之一,对于泥石流的研究思路的进一步发展和完善,在很大程度上将对山区的工程建设有很重要的指导意义。从工程地质研究思路的角度出发,对位于川藏公路二郎山隧道西口和平沟泥石流进行了研究。采用工程地质分析的方法对和平沟泥石流的形成环境(地层岩性条件、构造条件、地貌条件、气象条件、植被发育及人类活动)、基本特征(泥石流沟的基本特征、泥石流的堆积特征)进行了系统的研究,并在此基础上对泥石流沟沿岸的岸坡稳定性(可能泥石流的物源)等进行了评价分析。对泥石流的活动趋势以及可能泥石流的方量做出了较为科学的评价预测。经过这样的系统分析对工程建设中的泥石流防治提出了治理设计方案。     

柳伊河水电站大坝右岸坝区研究

In the paper in order to ascertain the condition of the right-bank of the dam at the Vilyui hydroelectric power plant measurements are applied to obtain experimental date such as drilling borehole,hydrolocation and so forth. By finding out the distribution of the temperature field some corresponding measures are taken to improve the stability of the dam during the change of the ground temperature. And finally some conclusions are draw to the study.     

The organisation of fish assemblages in the regulated Lima basin, Northern Portugal

In order to understand the structure of fish assemblages in the modified Lima basin (Northern Portugal), two distinct datasets concerning the presence and abundance of fish species were subjected to multivariate analysis. On the River Lima two types of flow modification are present within kilometres of one another: (a) a reduced and constant flow due to hypolimnetic release; and (b) an intense and irregular flow. A comparison of their influence on fish assemblages revealed a gradient of assemblage types from tributaries to main river sites. The latter were characterised by a strong dominance of cyprinids, particularly Iberian barbel (Barbus bocagei). The former harboured two kinds of fish assemblages: those closer to the river mouth were dominated by the cyprinids Iberian chub (Squalius carolitertii) and Iberian nase (Chondrostoma polylepis), which were also frequently present in the main river; while in those further upstream the predominant species was the brown trout (Salmo trutta). Although explanatory variables such as distance from source, altitude, substrate coarseness and width were the primary correlates of fish assemblage composition, dam construction and flow regulation also had a significant effect upon assemblage structure, particularly by: i) reducing the importance of migratory species; ii) constraining the presence of trout in the regulated segments; and iii) simplifying the community, especially in the case of the constant and reduced flow regime.     

Are open fractures necessarily aligned with maximum horizontal stress?

Fluid flow in fractured rock is an increasingly central issue in recovering water and hydrocarbon supplies and geothermal energy, in predicting flow of pollutants underground, in engineering structures, and in understanding large-scale crustal behaviour. Conventional wisdom assumes that fluids prefer to flow along fractures oriented parallel or nearly parallel to modern-day maximum horizontal compressive stress, or S_Hmax. The reasoning is that these fractures have the lowest normal stresses across them and therefore provide the least resistance to flow. For example, this view governs how geophysicists design and interpret seismic experiments to probe fracture fluid pathways in the deep subsurface. Contrary to these widely held views, here we use core, stress measurement, and fluid flow data to show that S_Hmax does not necessarily coincide with the direction of open natural fractures in the subsurface (>3 km depth). Consequently, in situ stress direction cannot be considered to predict or control the direction of maximum permeability in rock. Where effective stress is compressive and fractures are expected to be closed, chemical alteration dictates location of open conduits, either preserving or destroying fracture flow pathways no matter their orientation.     

FLOW FIELD IN SCOURED ZONE OF CHANNEL CONTRACTIONS

Experiments were conducted in a laboratory flume to measure the two-dimensional turbulent flow field in the scoured zone of channel contractions under a clear-water scour condition. The Acoustic Doppler Velocimeter (ADV) was used to detect the flow field at different vertical lines along the centerline of uncontracted (main channel) and contracted zones of the channel. The distributions of time-averaged velocity components, turbulent intensity, turbulent kinetic energy, and Reynolds stresses are presented in nondimensional graphical form. The bed shear stresses are computed from the measured Reynolds stresses being in threshold condition within the zone of contraction where bed was scoured. The data presented in this paper would be useful to the investigators for the development of kinematic flow model and morphological model of scour at a channel or river contraction.     

山西省主要河流流域面雨量预报业务流程

以T213、HLAFS模式、MM5中尺度模式输出的格点资料以及日本降水量格点资料为基础，将影响山西降水的天气动力模型归纳为诊断模型，从中引出多个能够全面反映降水模型特征的综合物理因子；根据各种数值模式输出的降水量预报性能和质量优劣特点，依据数值模式的形势场预报优于要素场预报的现实，构造在不同环流形势背景下，启动不同预报方程的面雨量预报业务流程，有效地遏止了在环流形势调整时预报输出不能快速响应的弱点，提高了点和面雨量预报的准确度。     

北京连续降雪过程分析

该文对2002年12月份北京出现的1841年以来历史上最长的连续6天的降雪天气进行了合成分析和诊断分析。北半球合成环流形势显示，连续降雪发生在东亚稳定的纬向环流形势下，其上游地区强大经向环流和阻塞高压使中纬度东亚和西太平洋纬向环流得以维持。东亚合成环流的垂直结构表明，连续降雪期间华北地区始终处于锋区中，并存在低空辐合、高空辐散的散度场垂直分布结构。卫星水汽云图显示出有水汽通道向河套倒槽云系输送水汽。华北地区的诊断分析表明，地面和边界层中山东地区分裂高压南侧向北回流的偏南气流是造成降雪的主要水汽通道。变形场的流场结构使水汽在北京附近辐合。垂直剖面展现了华北回流降雪天气近地面层的浅薄的冷空气垫，和暖湿空气回流在冷空气垫上的爬升，并在其上形成一个浅薄的饱和层。