基于小波分析的场地波速测量方法

在场地波速测量中,由于噪声等因素的影响很难准确识别P、S波的初至时刻,致使波速结果存在很大的误差。本文给出了一种基于小波变换的波速测量的新方法。该方法利用波动信号的小波变换与弹性波群速度的关系准确识别弹性波初至时刻。弹性波小波变换的峰值时刻代表着以群速度传播的弹性波的初至时刻,使P波、S波的初至时刻的确定具有明确的物理意义,波速的结果准确、可靠、稳定。此外,波动信号的小波多尺度分析还可以确定地层中传播的弹性波的频散特性。最后,该方法在场地波速测量的实测信号的应用表明该方法可准确确定P、S波速。     

小体积液液萃取气相色谱-质谱法测定地下水中的克百威与3-羟基克百威

克百威和3-羟基克百威是一对典型的农药母体及其代谢产物,由于其水溶性高、毒性大,可通过地表水或地下水进行长距离迁移,对人类健康和环境安全造成危害.以往通常采用液相萃取或固相萃取的方式提取样品中的克百威和3-羟基克百威,但这些方法操作繁琐、耗时较长,不利于室内模拟实验中多组样品的检测.为实现克百威与3-羟基克百威在地下水...     

Spatial variation and driving mechanism of soil organic carbon components in the alluvial/sedimentary zone of the Yellow River

Alluviation and sedimentation of the Yellow River are important factors influencing the surface soil structure and organic carbon content in its lower reaches. Selecting Kaifeng and Zhoukou as typical cases of the Yellow River flooding area, the field survey, soil sample collection, laboratory experiment and Geographic Information System(GIS) spatial analysis methods were applied to study the spatial distribution characteristics and change mechanism of organic carbon components at different soil depths. The results revealed that the soil total organic carbon(TOC), active organic carbon(AOC) and nonactive organic carbon(NOC) contents ranged from 0.05–30.03 g/kg, 0.01–8.86 g/kg and 0.02–23.36 g/kg, respectively. The TOC, AOC and NOC contents in the surface soil layer were obviously higher than those in the lower soil layer, and the sequence of the content and change range within a single layer was TOCNOCAOC. Geostatistical analysis indicated that the TOC, AOC and NOC contents were commonly influenced by structural and random factors, and the influence magnitudes of these two factors were similar. The overall spatial trends of TOC, AOC and NOC remained relatively consistent from the 0–20 cm layer to the 20–100 cm layer, and the transition between high-and low-value areas was obvious, while the spatial variance was high. The AOC and NOC contents and spatial distribution better reflected TOC spatial variation and carbon accumulation areas. The distribution and depth of the sediment, agricultural land-use type, cropping system, fertilization method, tillage process and cultivation history were the main factors impacting the spatial variation in the soil organic carbon(SOC) components. Therefore, increasing the organic matter content, straw return, applying organic manure, adding exogenous particulate matter and conservation tillage are effective measures to improve the soil quality and attain sustainable agricultural development in the alluvial/sedimentary zone of the Yellow River.     

倾斜固体潮对我国若干地震的触发作用浅析

本文研究了我国历史与现今中强以上地震的发震时刻与倾斜固体潮的关系。结果表明,地震发震时刻位于震中区当天倾斜固体潮的峰值时段上。孤立型地震的发震时刻往往与震中区倾斜固体潮极大值对应;原地重复发生的地震,其发震时刻所处的倾斜固体潮背景相同;逼近地震与主震发震时刻的倾斜固体潮背景相同的占70%;大震后有60%的强余震与主震发震时刻的倾斜固体潮背景相同。据此,成功地预报了门源6.4级地震后的较大余震。     

Finite Element Analysis of Crossing Flow in an Intersected Fracture by Penalty Function Formulation

On the basis of Navier-Stokes equation, a digital analogue of crossing flow is carried out by means of finiteelement analysis performed through penalty function formulation. The results of the digital analogue are ingood agreement with that of the previous hydraulic physical simulation. They both demonstrate the effect of"deflection flow" occurring at the fracture intersection that the fracture-water crossing flow deflects △q intothe wide fracture.     

关于我国的盐溶角砾岩

盐溶角砾岩可分为溶解-崩塌角砾岩和塑变-交代角砾岩两种类型。它们的主要鉴定特征是分布的层位稳定、角砾成分单一,而且无例外地均和易溶蒸发盐岩伴生。我国主要成盐期的地层中,均有盐溶角砾岩分布,不过发育的程度和特点略有不同。     

金沙江—澜沧江—怒江地区金矿类型及成矿条件

金沙江-澜沧江-怒江地区是中国重要的贵金属、有色金属成矿远景区之一。金矿类型繁多,主要有:蛇绿混杂岩中的构造蚀变岩型;与中酸性岩浆侵入活动有关的多金属石英脉型;构造破碎带中的微细浸染型;碳酸盐岩层构造裂隙中的混成热液型;与次火山岩有关的热液型;火山热泉型和海底火山喷流沉积-热液改造型。成矿时间集中于中新生代。矿床和矿体主要受线型构造控制。岩浆活动在金的成矿过程中有不同程度影响。金矿基本属浅成、中低温热液型。蚀变作用普遍强烈。成矿物质及热液具多源性。     

山地制度建设试验与思考

本试验针对怀化地区山地制度建设问题,通过建立山地档案制度,使山地产权制度、使用权流转制度和山地开发管理制度更趋规范化、科学化,消除由于流转不规范而影响山地开发的隐患,对促进山地的集中,规模开发和利用,提高山地生产力取得了明显的成效。     

CHANGE OF CLIMATE AND ITS INFLUENCE ON THE CROPPING SYSTEM IN CHINA

Tne global change of climate and its influence on the cropping system in China have been investigatedin this paper.It is found that the temperature was increased during the last decade and the precipitationdecreased in northern China and increased in southern China during the last 30 years.The sea level hasbeen rising by about 21—26 cm in the coastal areas south of 30°N in China during the last 100 years.The most of results as simulated by the general circulation models(GCMs)show that the temperature increasewould amount to about 2°—4°C in the most parts of China and precipitation and soil moisture might bedecreased in northern China and increased in sourthern China due to doubling of carbon dioxide(CO_2).The effects of doubled CO_2 on growth period and climatic yield capability in China have been estimatedroughly.It is shown that the regions of the growth period in China would be moved northward about fivedegrees latitude and the climatic yield capability might be increased by about 10％ in the most parts of China.