Effects of grass contour hedgerow systems on controlling soil erosion in red soil hilly areas,Southeast China

Soil erosion by water is a well-recognized serious environmental problem in the world.While contour hedgerow systems are an effective method for soil water conservation,there are a few studies on its effect in the red soil hilly areas in Southeast China.With a fixed field experiment,we constructed a runoff plot at hilly area in Zhuji County,Zhejiang province,to evaluate the effect of the grass hedgerows in soil water conservation,and to determine the optimized hedgerow patterns.Hemerocallis citrine(HC)and Ophiopogon japonicas(OJ) were selected to build the hedgerows in patterns of one row and two rows.The REE method was used to trace the source of the sediment for a better understanding of the characteristic and mechanism of erosion with hedgerows control.Our results showed that(1) hedgerows reduced erosion and surface runoff by 31.99-67.22%and 15.44-45.11%,respectively;(2) hedgerows delayed the development of rills;(3) hedgerows reduced the soil nutrients loss;(4) hedgerows reshaped the soil physical properties,especially in increasing > 0.25 mm water-stable aggregates.Taken together,our results suggest that two-row OJ is the optimized contour hedgerow pattern in the experiment condition,and downward sloping land should have the highest priority to take measures for soil water conservation.This research comprehensively studied the effects and mechanism of contour hedgerows in controlling soil and water loss in red soil hilly areas,Southeast China,so that the practice of soil and water conservation can be implemented more effectively in these areas.     

用SVG实现基于 Web的地震数据图形化服务

SVG是一种基于XML的用来描述二维矢量的标志语言,是一种全新的矢量图形规范,为了能够对相关人员提供方便直观快捷的地震数据表现形式,本文对利用SVG实现地震数据图形化表示的方法进行了讨论与研究。     

1999年四川绵竹清平5.0级地震序列构造活动特征

1999年9月14日四川绵竹清平5．0级地震序列是近年发生在青藏高原碰撞带东南边界的龙门山断裂带的规模最大的一次地震活动。本文通过对序列地震震源位置的精确确定，对主要的8次地震震源机制的求解和时间进程中震级频次变化的分析，来揭示该震源区地下构造的活动特征。结果表明：（1）前震－主震－余震的时间进程完整，只是衰减较快。（2）主震位于龙门山中央主断裂弯折的端头，与同震中十分接近。大部分余震分布在中央主断裂一侧的次级隐伏构造地带，与主断裂的北东走向一致。震源深度3－15km，（3）震源断层面北东取向，在指向南东的近水平方向的主压应力作用下，断层面的锚动以逆冲兼走滑的方式为主，间有少量小型的正断层活动，统一呈现出地下物质向南东的滑移。     

Measurement of surface water runoff from plots of two different sizes

Intensities and amounts of water infiltration and runoff on sloping land are governed by the rainfall pattern and soil hydraulic conductivity, as well as by the microtopography and soil surface conditions. These components are closely interrelated and occur simultaneously, and their particular contribution may change during a rainfall event, or their effects may vary at different field scales. The scale effect on the process of infiltration/runoff was studied under natural field and rainfall conditions for two plot sizes: small plots of 0·25 m² and large plots of 50 m². The measurements were carried out in the central region of Chile in a piedmont most recently used as natural pastureland. Three blocks, each having one large plot and five small plots, were established. Cumulative rainfall and runoff quantities were sampled every 5 min. Significant variations in runoff responses to rainfall rates were found for the two plot sizes. On average, large plots yielded only 40% of runoff quantities produced on small plots per unit area. This difference between plot sizes was observed even during periods of continuous runoff. Copyright © 2002 John Wiley & Sons, Ltd.     

绵竹市旅游资源评价

作者从绵竹的资源入手，作了充分且实际的自身评价，并与区域旅游资源进行了比较评价，找到绵竹旅游的准确位置，进一步分析了绵竹市旅游资源在四川省旅游业的地位和作用。     

改良的数字化测图新方法

阐述了在地形复杂、地貌破碎、作业组较多时一种改良的数字化测图新方法的作业流程。该方法发挥了数字化测图的高精度高效率和模拟法测图善于处理勾绘复杂地貌等高线的长处，为针对不同情况制定合适的测图作业方案增加了一种选择。     

基于Microstation图形工作站的城区防洪图的设计与编制

本文从城市体系的构成出发，论述了城区防洪图的组成。结合《江苏省水利地图集》的制作，对该图种的用途、要求、资料使用情况及作业方法都作了简要说明；详细介绍了城区防洪图的编绘内容及表示方法。最后基于Microstation工作站，从符号系统、截幅到编绘效率及编绘过程中几个实际问题作了具体分析。     

鄂尔多斯盆地南缘早古生代碳酸盐岩高频沉积旋回分析

鄂尔多斯盆地南缘早古生代碳酸盐岩台地的演化可分低能和高级缓坡、具局限性内陆架盆地的镶边陆架、虎蒸发性内陆架盆地的镶边陆架及断边缘４个阶段，在不同的演化 ，高频沉回旋类型具有明显差异，说明沉积背景控制了碳酸盐岩高频沉积旋回的复杂性、多样性、根据对和线个演经阶段高频旋回的分级栩比及周期计算表明，其驱动机制应与米兰科维奇的天文轨道有关。     

REVIEW ARTICLE MULTIVARIATE EXPLORATORY DATA ANALYSIS AND GRAPHICS:A TUTORIAL

Exploratory data analysis(EDA)is a toolbox of data manipulation methods for looking at data to seewhat they seem to say,i.e.one tries to let the data speak for themselves.In this way there is hope thatthe data will lead to indications about'models'of relationships not expected a priori.In this respect EDAis a pre-step to confirmatory data analysis which delivers measures of how adequate a model is.In thistutorial the focus is on multivariate exploratory data analysis for quantitative data using linear methodsfor dimension reduction and prediction.Purely graphical multivariate tools such as 3D rotation andscatterplot matrices are discussed after having introduced the univariate and bivariate tools on which theyare based.The main tasks of multivariate exploratory data analysis are identified as'search for structure'by dimension reduction and'model selection'by comparing predictive power.Resampling is used tosupport validity,and variables selection to improve interpretability.