Long‐term effects of revegetation on soil hydrological processes in vegetation‐stabilized desert ecosystems

Planting of sand‐binding vegetation in the Shapotou region on the southeastern edge of the Tengger Desert began in 1956. The revegetation programme successfully stabilized formerly mobile dunes in northern China, permitting the operation of the Baotou‐Lanzhou railway. Long‐term monitoring has shown that the revegetation programme produced various ecological changes, including the formation of biological soil crusts (BSCs). To gain insight into the role of BSCs in both past ecological change and current ecological evolution at the revegetation sites, we used field measurements and HYDRUS‐1D model simulations to investigate the effects of BSCs on soil hydrological processes at revegetated sites planted in 1956 and 1964 and at an unplanted mobile dune site. The results demonstrate that the formation of BSCs has altered patterns of soil water storage, increasing the moisture content near the surface (0–5 cm) while decreasing the moisture content in deeper layers (5–120 cm). Soil evaporation at BSC sites is elevated relative to unplanted sites during periods when canopy coverage is low. Rainfall infiltration was not affected by BSCs during the very dry period that was studied (30 April to 30 September 2005); during periods with higher rainfall intensity, differences in infiltration may be expected due to runoff at BSC sites. The simulated changes in soil moisture storage and hydrological processes are consistent with ongoing plant community succession at the revegetated sites, from deep‐rooted shrubs to more shallow‐rooted herbaceous species. Copyright © 2009 John Wiley & Sons, Ltd.     

几种不对称变色酸双偶氮胂类显色剂与钍的显色反应

本文较详细地研究了6种不对称变色酸双偶氮胂类显色剂与Th的显色反应,并对各自与Th形成络合物的条件和主要干扰离子的允许量、灵敏度等方面做了比较,以求推荐出优于偶氮胂Ⅲ,并适于不同成分样品特点的有效显色剂,供有关分析部门测定Th时参考选用。     

Evolution and REE geochemistry of Huangsha-Tieshanlong ore-bearing granite

Our studies show that the granite bodies (γ ₅ ^{2 − 1} and γ ₅ ³ ) which constitute the Huangsha-Tieshanlong composite granitic intrusion in Jiangxi are characterized by their similarities in mineral assemblage, petrochemistry, trace element and REE distribution pattern. The values of ΣREE, ΣLREE, ΣHREE, ΣCe/ΣY, δEu and La/Yb apparently decrease from γ ₅ ^{2 − 1a} to γ ₅ ^{2 − 1b} , γ ₅ ³ and γ ₅ ³ . It is shown that the early Yenshanian W(Ta, Nb)-bearing granite (γ ₅ ^{2 − 1} ) and late Yenshanian Ta, Nb-bearing granite (γ ₅ ³ ) may have been derived from the differentiation and evolution of granitic magmas due to repeated remelting of the crust and their earlier and later intrusion. Although the earlier (γ ₅ ^{2 − 1b} and later (γ ₅ ³ ) albitized Ta, Nb-bearing granites show some obvious differences in REE content, their δEu values and La/Yb ratios are similar to each other. Therefore, it may be concluded that the early and late Ta, Nb-bearing granites were derived from a congenetic magma.     

Application of Hydro-Electric Effect Method to NDI of Piles

This paper presents briefly the essential principle and measurement process of hydro-electric effect method for NDI of piles. In the past three years, more than three hundred piles from twenty project sites inspected with method. Coring piles and comparing dynamic with static tests have proved that hydro-electric effect method is available for engineering with easy operation, quick inspection, and low costs.     

Seepage and Deformation of Fissured Rock Mass

Seepage law of fissured rock masses is presented in this paper. The Navier-stokes equation is demonstrated available to describe seepage law of rock masses by testing study. The dynamical seepage pressure in rock masses makes great effect on deformation of rock masses, results in opining of fissure and deformation of rock masses. The seepage and deformation of rock mass and dynamical seepage pressure is studied. The experimental results are checked with Bossiness formula, and are closed to the computing data.     

江西弋阳港口盆地林山组地层时代讨论

本文讨论了江西弋阳港口盆地林山组中的植物化石群。根据其组份特征,可确定该地林山组时代为早侏罗世中晚期,可与鄂西香溪组中下部的植物群对比。     

广东省海岸表层沉积物的重矿物特征及其与沉积环境的关系

广东省海岸表层沉积物中的重矿物近40种。含量较高的有钛铁矿、赤矿铁、磁铁矿、话石、电气石、黑云母和普通角闪石等。自生矿物主要为硬石膏、自然铜、黄铁矿及菱铁矿。这些矿物来自附近的母岩。根据物源性质不同,可将不同岸段重矿物区分为陆源矿物组合、近源-自生矿物组合和近源矿物组合三种:除物源控制外,重矿物含量、种类、形态特征及其在平面上的分布主要受沉积环境影响。据此,可将重矿物分布类型划分为河口型、海湾型和海岛型三类,且与上述不同矿物组合性质相对应。     

云南省潜在震源区综合统计判定之一

本文将云南省地震局多年来积累的关于中强震发生的地质构造、地貌、地球物理场、地形变等特征基础资料,用于Cora-3算法的模式识别,得出云南省潜在震源区的背景指标,结果是比较理想的。“投票”结果表明,80%的学习集D类对象仍被识别为D类,85%的学习集N类对象仍被识别为N类,控制试验的结果也表明识别结果是比较稳定和可靠的。     

Structural Styles of the Longmenshan Thrust Belt and Evolution of the Foreland Basin in Western Sichuan Province, China

The Longmenshan thrust system consists of two major groups of structural styles according to the depth of their involvement: basement thrusts-compressional fault blocks; fold-thrust system in the cover. In cross-section, the Longmenshan structural belt is divided into 5 zones. The propagation of the Longmenshan thrust system is piggy-back due to pushing at the early stage and overstep due to gravity sliding at the late stage. Balanced cross-sections and palinspastic reconstruction reveal that the total sliding displacement of the thrust system amounts to 120 km. The tectonic evolution of the Tethys domain in western Sichuan has experienced 5 stages: continental break-up; ocean-continent subduction ; continent-arc collision; orogenic thrusting; uplift of western Sichuan.