锚杆腐蚀与防腐保护   总被引：5，自引：0，他引：5  

黄育  郭志昆  向晓峰 《岩土工程技术》2004,18(5):263-266

实际工程中 ,锚杆腐蚀引起结构严重的破坏屡见不鲜。概述了锚杆发生腐蚀的条件和腐蚀类型 ,分析了影响锚杆腐蚀的主要因素 ,提出了防腐蚀保护的基本要求及防腐蚀保护的相关措施  相似文献   

Dynamic analysis and evaluation of Xinjiang forest resources: based on RS and GIS   总被引：1，自引：0，他引：1  

LI Hu  WANG Xiaofeng  CHEN Shujiang 《地理学报》2005,15(3):346-352

The forest resources in Xinjiang were surveyed and analyzed based on RS and GIS. Satellite data interpretation was adopted to obtain the general situation of Xinjiang forest resources in assistance with the sampling method and on-the-spot investigations. Based on GIS, related data obtained from satellite remote sensing in 1996 and 2001 were studied through contrastive analysis. Moreover, the dynamic variation of Xinjiang forest resources was studied in an all-around way. In the past five years, the areas of the forestland, woodland, sparse woodland, nursery garden and the land usable for forestry in Xinjiang kept growing, moreover, the forest cover rate and the total standing stock volume increased correspondingly, showing that the wooded area and the amount of growing stock in Xinjiang were increasing. The forestland area in Xinjiang went up to 17,837 km2 from 17,331 km2, with an annual average increase of 101 km2. Accordingly, the forest vegetation came to 1.08% from 1.05%, up 0.03 percentage point; the total standing stock volume went up to 289,985,200 m3 from 262,416,000 m3, a total increase of 27,569,200 m3, an annual average increase of 5,514,000 m3 and an annual average net growth rate of 2.00%. The analysis results showed that the forest resources in Xinjiang were increasing on the whole, however, there remained some problems, such as the sparse natural forests, low forest cover rate, imbalanced wood age structure, and mono tree species composition, etc.  相似文献   

Paleoenvironmental significance investigation of loess magnetic fabric in a semiarid region     

WANG Yong  PAN Baotian  GUAN Qingyu  GAO Hongshan  ZHANG Hui  LI Qiong  LIU Xiaofeng 《地理学报》2005,15(2):210-216

Here we report our recent magnetic fabric investigation of loess deposition in Shagou section, located at the northeastern Qilian Mountains, the northeastern rim of the Tibetan Plateau. On the basis of environmental magnetism data, we indicate that the variation of anisotropy of magnetic susceptibility (AMS) parameters, especially the foliation (F) and degree of anisotropy (P), might be more sensitive to the environmental change in the arid and semiarid regions than the magnetic susceptibility fluctuation. During the investigated interval, from 0.83 to 0.128 Ma, most of the middle to late Pleistocene significant climate change can be unraveled by the AMS parameters, such as the strengthening of cold/dry climate, the step drying event occurred nearly 250 ka, and the severe environmental change in MIS16. Our results also suggest that there is strong correlation between median diameter (Md) of grain size, F, and P. We propose that the AMS parameters can act as an important paleoenvironmental change indicator in the arid and semiarid regions.  相似文献   

论陆相含油气沉积盆地地下水动力场与油气运移、聚集   总被引：16，自引：4，他引：16       下载免费PDF全文

楼章华  金爱民  田炜卓  蔡希源  高瑞祺 《地质科学》2005,40(3):305-318

含油气沉积盆地地下水动力场的形成、演化是沉积盆地演化在孔隙流体中的综合反映,它直接受盆地地貌、水文网、沉积环境、构造性质及其演化史的控制。地下水动力场的形成、演化与油气的运移、聚集和分布规律具有十分密切的关系。含油气沉积盆地通常经历了多期水文地质旋回,从而决定了在一个独立的水动力体系中油气阶段性运移和阶梯式—环带状分布的特点。油气的阶梯式—环带状分布以沉积凹陷控制的包括部分相邻三级构造单元的具有相对独立的水动力体系为基本单元。因此,作为一个具有多个沉积凹陷的盆地来说,油气的分布通常由多个环带复合而成。  相似文献   

深部流体及其与成矿成藏关系研究现状   总被引：18，自引：0，他引：18  

毛景文  李晓峰 《矿床地质》2004,23(4):520-532

深部流体(地幔流体)及其成岩成矿作用的研究是当今地质科学研究的前沿领域，最近几年这方面的研究进展较快。文章比较详细地讨论了地幔流体的组成、地幔流体中碳氧、氢氧和稀有气体同位素特征、地幔流体类型和运移形式，以及地幔流体活动的构造背景，并对地幔流体与金属矿床、油气田盆地等成矿成藏作用关系的研究现状进行了介绍。  相似文献   

Analysis and assessment of land desertification in Xinjiang based on RS and GIS     

LI Hu  WANG Xiaofeng  GAO Yaqi 《地理学报》2004,14(2):159-166

The land desertification in Xinjiang was monitored and analyzed based on RS and GIS techniques. Satellite data interpretation was adopted to obtain the general situation of Xinjiang's land desertification in assistance with the sampling method and on-the-spot investigations. Related monitoring and investigations showed that Xinjiang was facing with severe wide range land desertification, and its desertified area made up 77.08% of the total monitoring area. As for land types, the desertified farmland accounted for 1.92% of the total monitoring area, desertified woodland 4%, desertified grassland 45%, and unused land 49%. Accordingly, as for desertification degrees, non-desertified land occupied 22.92%, weak desertified land 5.69%, medium-degree desertified land 16.58%, severe desertified land 33.19% and super severe desertified land 21.61%. Finally, as for inducing factors, wind-eroded desertification made up 58.23%, water-eroded desertification 8.69%, salinization desertification 6.52% and frozen-melt eroded desertification 3.64%. Xinjiang's land desertification tended to get worse and the harnessing mission remained hard.  相似文献   

结构状态智能模拟技术研究     

钟珞  袁景凌  楼梦麟 《武汉大学学报(信息科学版)》2005,30(10):932-935

提出了一套结构状态智能模拟技术,融结构分析方法和计算机技术为一体,主要将信息处理智能方法应用到结构状态的模拟及可视化中,并结合了混合编程技术、可视化技术、基于XML的接口技术、软构件技术及工程数据库技术等,提出了智能可视化的概念。研究了两种基于灰色系统的改进的小样本数据可视化预测模型,并以基于XML可视化接口为基础,应用智能模拟技术,建立结构状态智能模拟环境的基本骨架。  相似文献   

无模糊度和整周跳变问题的短基线解算方法研究     

楼益栋  李征航  张小红 《武汉大学学报(信息科学版)》2005,30(11):995-998

提出了一种不涉及模糊度和整周跳变问题的短基线解算方法。用自编软件对实际观测资料进行了处理。计算结果表明,本方法的原理和数学模型是正确的,对于一般静态短基线解算,平面精度达到2mm左右,高程精度达到5mm左右。  相似文献   

声波及弹性波地震模拟的无网格算法   总被引：1，自引：1，他引：1  

贾晓峰  胡天跃  王润秋 《应用地球物理》2005,2(1):1-6

波动方程方法是地震模拟和成像的基本方法之 一。本文利用无单元法(EFM)处理地震模拟中的 声波及弹性波波动方程。无单元法中没有单元的 概念,使节点完全摆脱了单元网格的束缚;此外, 采用滑动最小二乘(MLS)准则使得方程的解高次 连续。本文将分别针对声波方程和弹性波波动方 程详细讨论无单元法的原理及吸收边界问题。在 此基础上,通过几个叠前模型的试算验证无单元 法用于地震模拟的有效性。  相似文献   

西藏措勤-申扎地层分区新建中--上侏罗统仁多组   总被引：1，自引：0，他引：1  

赵兵刘登忠  陶晓风马润则　胡新伟 《地质通报》2005,24(7):637-641

在西藏措勤西部昂拉仁错南部新发现一套侏罗纪地层，其岩性和古生物组合特征均不同于邻区侏罗系。通过详细的层型剖面测制和对比研究，将其新建为组级岩石地层单位——仁多组。指定并详细描述了正层型剖面，讨论了仁多组的岩石组合特征、地层接触关系、基本层序和沉积环境。根据仁多组的生物化石组合及其地层分布建立了2个生物组合带，并确定仁多组下段与中-上段分属为中、上侏罗统。仁多组的建立为认识区域地层系统及地质演化提供了新资料。  相似文献