塔里木河流域出山径流水化学特征研究

本文以区域地质为背景,对塔里木河流域山区径流水化学组分特征进行分析,探讨溶质的来源及其控制因素.结果表明：塔里木河流域出山径流水体以硅酸盐岩的碳酸化溶滤水为主,离子类型为HCO₃^--Ca²⁺型,其次为SO₄^2--（Ca²⁺+Mg²⁺）混合型.南缘昆仑山/帕米尔高原各子流域的出山径流中,TDS （溶解性总固体）和离子总量的加权平均值（权重为径流量）分别为424.02和356.20 mg/L,远高于北缘天山出山的相应值（268.43和220.04mg/L）,这是因为天山山区分布大量的岩浆岩,抑制了区域水化学侵蚀强度.运用吉布斯图及因子分析等方法,确定出山径流的水质主要受硅酸盐岩的碳酸化作用控制,其中南缘昆仑山/帕米尔高原水系不仅伴有蒸发盐岩风化,还与天山阿克苏河水系一样,伴有碳酸盐岩风化.风化过程中,硫化物氧化产生的H⁺抑制了碳酸化风化,一定程度上限制了大气CO₂消耗,尤其是在有煤层、铜矿等硫化物分布的迪那河、喀拉玉儿滚河和喀什葛河流域.塔里木河流域出山径流中除了F^-和NO₃^-外,其他离子和总离子浓度均与冰川覆盖率和融水占径流比例之间存在良好的相关性.总离子浓度与冰川覆盖率之间建立的指数拟合方程,符合我国西北干旱区出山水质的特点,但受自然与人为因素的制约,与全球尺度拟合的方程存在一定差异.     

Fisher法确定稳定分类数

对Fisher法确定稳定分类数作了一些改进,提出利用β值指标来衡量分类的稳定程度,进而确定合理的分类个数。在实际应用中,证明了该方法是可行的。     

煤岩瓦斯复合动力灾害机理研究进展与展望

随着我国煤矿快速进入深部开采,煤岩瓦斯复合动力灾害日渐成为威胁深部煤炭安全高效开采的重大灾害,研究其发生机理成为煤矿安全领域新的重大科学问题。本文首先在调研统计的基础上,阐述我国煤岩瓦斯复合动力灾害的发生规律和主要破坏特征,从定性和初步定量研究角度对煤岩瓦斯复合动力灾害机理的研究现状进行综述分析,然后介绍笔者近年来在受载含瓦斯煤岩组合体耦合失稳诱发复合动力灾害机制方面的研究进展,最后展望煤岩瓦斯复合动力灾害机理研究中亟待解决的问题及未来研究方向。     

含裂隙岩石裂纹扩展与剪切特性的数值研究*

为研究直剪条件下含交叉裂隙岩石的裂纹扩展模式和剪切特性,基于PFC2D研究直剪条件下含裂隙岩石的裂纹扩展模式和剪切特性。研究结果表明:直剪过程可分4个阶段:Ⅰ初始平静阶段、Ⅱ裂纹单一扩展阶段、Ⅲ裂纹复杂扩展阶段、Ⅳ破坏阶段;法向应力越大,Ⅱ,Ⅲ阶段的裂纹扩展程度受到抑制;岩石中含单裂隙时,随裂隙角度α的增加,抗剪强度的变化趋势基本一致,遵循先降后增的规律;含交叉裂隙时,当主裂隙角度α=120°,150°时,抗剪强度随次裂隙角度β的增加呈先减小后增大的趋势,抗剪强度最小值均出现在β=30°;加固含裂隙岩体时,预防裂隙或者潜在破坏面两侧的岩体产生位移差,使其加固后成为1个稳固整体,是避免岩体产生裂纹导致破坏的重要手段。     

基于HFACS-BN模型的危险化学品事故人因路径分析*

为提高危险化学品安全管理水平,收集我国134起以人为主因的危险化学品事故,构建危险化学品事故的HFACS-BN模型,并基于贝叶斯网络对危险化学品事故中的人因路径及各因素灵敏度进行分析。研究结果表明:行为违规是导致事故的最主要不安全行为;在复杂路径中,环境因素和操作者状态具有较高的灵敏度,与其相关的风险认知与处理不当是阻碍事故预防的关键因素;在非复杂路径中,操作者状态与运行计划不当具有较高的灵敏度,其所涉及的监督违规、组织过程和组织氛围,是导致危险化学品事故的根本起点,并可依此分析事故直接原因和间接原因;操作者状态在2种路径中均表现出高灵敏度,因此化工企业在人员管理上要加强关注职工状态,减少不安全行为的出现。     

EVALUATION OF THE ROSGEN STREAM CLASSIFICATION SYSTEM IN CHEQUAMEGON‐NICOLET NATIONAL FOREST,WISCONSIN1

ABSTRACT: Data collected from 121 stream reaches during 1991 to 1993 were evaluated to determine the applicability of the Rosgen Stream Classification System (RSCS) to the low relief terrain within the Chequamegon‐Nicolet National Forest (CNNF) in Wisconsin, USA. All reaches were classified to RSCS Level I and II except that 10.7 percent had sinuosities below the continuum limits and one reach had a predominantly organic substrate. Five of eight possible RSCS Level I types were observed including B, C, D, A, E, and F; 86 percent were C and E types. Seventeen of 94 possible RSCS Level II types were observed. Most reaches were slightly entrenched, had low to moderate width/depth ratios, relatively low sinuosity, low slope, and sand or gravel as the dominant channel material. Discriminant analyses were used to verify the applicability of RSCS for streams within the CNNF; discriminant functions correctly classified 92.5 and 94.7 percent of the Level I and II RSCS types, respectively. When limits for E and F types were modified slightly at Level II by adding an additional category for slopes less than 0.1 percent (a modification we recommend for low relief terrain), discriminant functions correctly classified 99.1 percent of the types. Adding another slope break at 0.3 percent produced similar results. Based on our analyses, RSCS works well within the CNNF and is probably applicable to other areas with low‐relief terrain.     

无量纲廓线函数对稳定度分类的影响

讨论了无量纲廓线函数对稳定度分类标准计算结果的影响,利用北京325m气象铁塔的超声脉动资料和常规梯度观测资料,对4种无量纲廓线函数进行比较.结果表明,对于北京地区Businger-Hick公式最合适,风速比法稳定度分类标准不是稳定度级别的单调函数.     

INTEGRATING DEMOGRAPHIC AND LANDSAT (TM) DATA AT A WATERSHED SCALE1

ABSTRACT: Recurrent calls for integrated resource management urge that an understanding of human activities and populations be incorporated into natural resource research, management, and protection efforts. In this paper, we hypothesize that watersheds can be a valuable geography for organizing an inquiry into the relationship between humans and the environment, and we present a framework for conducting such efforts. The framework is grounded in the emerging field of landscape ecology and incorporates demographic theory and data. Demography has been advanced by technological capabilities associated with the 1990 Census. Employing Geographic Information System (GIS) tools, we couple Landsat Thematic Mapper (TM) land cover data with census‐derived housing density data to demonstrate the operation of our framework and its utility for better understanding human‐landscape interactions. In our investigation of the Kickapoo Watershed and two sub‐ watersheds, located in southwestern Wisconsin, we identify relationships between landscape composition and the distribution and social structure of human populations. Our findings offer insight into the interplay between people and biophysical systems.     

GHS化学品危险性分类及其公示要素(上)

概述了全球化学品统一分类和标签制度（GHS）的产生背景、推行GHS的重要意义,介绍了GHS关于化学品危险性分类和公示要素的主要内容,评估了我国现行化学品危险性分类与GHS分类的差异点,并对我国全面实施GHS提出了若干对策建议。     

高烈度地震区隧道软硬围岩交接段刚柔并济抗减震技术研究

为提高高烈度地震区隧道抗震性能,以某铁路隧道为研究背景,分析3种抗减震措施下隧道不同监测点隧道拱顶沉降、边墙收敛、衬砌结构PGA及最小安全系数,通过对比分析得到最优抗减震措施.结果表明:相比于工况1,工况2隧道拱顶沉降减小10.54％ ～81.10％,边墙收敛减小13.92％ ～78.77％,衬砌结构PGA减小31.4...