测老庙盆地水中铀的存在形式及其找矿意义

本文通过热力学的计算方法,确定了测老庙盆地水中铀的存在形式,分析了铀在水中的迁移规律和沉淀条件。并应用饱和指数的找矿机理,对测老庙盆地的找矿前景提出了水文地球化学依据。     

比值R分析及其在宁夏中强地震预报中的应用

本文提出比值Ｒ分析计算方法，用其求解时间序列数据矩平差和标准差结构的分形，目的的于判定地震预报指标，作为实例，宁夏区和同心区的地震频度，最大震级，以及同心地办水氡观测数据的比值Ｒ随时间的分形变化进行了初步分析，证明本方法能为我国提供可信的震情信息。     

义县留龙沟金矿含金矿物特征

本文对留龙沟金矿的矿物成分、共生关系、矿物生成顺序,成矿温度进行了一些研究,为探讨矿床成因提供一些资料。     

Effects of surface characteristics on infiltration patterns in an arid shrub desert

Precipitation is often the sole source of water replenishment in arid and semi‐arid areas and, thus, plays a pertinent role in sustaining desert ecosystems. Revegetation over 40 years using mainly Artemisia ordosica and Caragana korshinskii at Shapotou Desert Experimental Research Station near Lanzhou, China, has established a dwarf‐shrub and microbiotic soil crust cover on the stabilized sand dunes. The redistribution of infiltrated moisture through percolation, root extraction, and evapotranspiration pathways was investigated. Three sets of time‐domain reflectometry (TDR) probes were inserted horizontally at 5, 10, 15, 20, 30 and 40 cm depths below the ground surface in a soil pit. The three sets of TDR probes were installed in dwarf‐shrub sites of A. ordosica and C. korshinskii community with and without a microbiotic soil crust cover, and an additional set was placed in a bare sand dune area that had neither vegetation nor a microbiotic soil crust present. Volumetric soil moisture content was recorded at hourly intervals and used in the assessment of infiltration for the different surface covers. Infiltration varied greatly, from 7·5 cm to more than 45 cm, depending upon rainfall quantity and soil surface conditions. In the shrub community area without microbiotic soil crust cover, infiltration increased due to preferential flow associated with root tunnels. The microbiotic soil crust cover had a significant negative influence on the infiltration for small rainfall events (～10 mm), restricting the infiltration depth to less than 20 cm and increasing soil moisture content just beneath the soil profile of 10 cm, whereas it was not as strong or clear for larger rainfall events (～60 mm). For small rainfall events, the wetting front depth for the three kinds of surface cover was as follows: shrub community without microbiotic soil crust > bare area > shrub community with microbiotic soil crust. In contrast, for large rainfall events, infiltration was similar in shrub communities with and without microbiotic soil crust cover, but significantly higher than measured in the bare area. Soil water extraction by roots associated with evapotranspiration restricted the wetting front penetration after 1 to 3 h of rainfall. Copyright © 2006 John Wiley & Sons, Ltd.     

塔克拉玛干沙漠腹地复合沙垄的流场和上覆沙丘组合及动态特征

复合沙垄是最大的沙丘地貌类型之一，表现为简单沙丘类型的垂直叠加和水平连接，在沙垄的高大地形影响下，沙垄不同部位形成不同的风沙环境特征。以塔克拉玛干沙漠腹地/复合沙垄为例，通过野外实地观测研究其流场和上覆沙丘组合特征。研究结果表明，复合沙垄的流场可分为沙垄迎风坡气流加速区、沙垄背风坡气流转向减速区、垄间粗沙平地气流风速风向恢复区和气流风速稳定区。受沙垄流场和地形的控制，沙垄上覆新月形沙丘链，垄间地分有简单新月形沙丘、沙堆、沙片、侵蚀地、简单线形沙丘。上覆沙丘分布特征表现为：垄间地上覆新月形沙丘疏密度较小，沙垄迎风坡和沙垄背风坡上覆新月形沙丘疏密度较大，而且超过1，说明沙垄迎背风坡上覆沙丘有叠置现象。沙垄上覆沙丘高度自沙垄迎风坡底部到顶部增高，背风坡上覆沙丘高度自沙垄顶部到背风坡底部减小，上覆沙丘在自身形态、地形和流场的共同影响下，存在相对运动，表现为分布进一步集中，因此沙垄有增高的趋势。     

广州市社会空间景观形态演化初探

相对于形体空间而言 ,社会空间是一个更深层面的城市空间领域 ,在城市形体空间日新月异的嬗变中 ,社会空间内涵的演化显得更为缓慢和深刻。以广州市为例 ,探讨这种景观形态演化的特性及其对现代城市形象建设和个性塑造的意义。     

星状沙丘研究进展综述

本文阐述了近年来的星状沙丘方面的研究进展，介绍了国内外星状沙丘的形成发育模式，粒度特征和沉积构造特征方面的理论及研究进展。