东半球空间环境地基综合监测子午链简介

“东半球空间环境地基综合监测子午链”（简称子午工程）是我国空间科学领域开工建设的第一个国家重大基础设施项目。子午工程利用沿东半球120°E子午线附近和北纬30°N附近的15个综合性观测台站,运用无线电、地磁、光学和探空火箭等多种探测手段,连续监测地球表面20—30km以上到几百公里的中高层大气、电离层和磁层,以及十几个地球半径以外的行星际的空间环境参数。它将为我国各类用户提供完整、连续、可靠的多学科、多层次的空间环境地基综合监测数据。子午工程总投资1．67亿元,建设期3年,子午工程整体科学寿命预计超过11年。     

龙滩库区蓄水初期水库诱发地震活动分析

龙滩水利枢纽位于广西天峨,是一座典型高坝大库容水库。本文通过对库区及周围的地质构造和蓄水前后地震活动分析,总结了龙滩水库蓄水初期诱发地震的时间、空间和深度分布特征以及蓄水后库区水位变化与地震活动关系,讨论了龙滩库区蓄水初期诱发地震机理。     

Spectral element analysis on the characteristics of seismic wave propagation triggered by Wenchuan <Emphasis Type="Italic">M</Emphasis><Subscript>s</Subscript>8.0 earthquake

The 2008 Wenchuan earthquake occurred in an active earthquake zone, i.e., Longmenshan tectonic zone. Seismic waves triggered by this earthquake can be used to explore the characteristics of the fault rupture process and the hierarchical structure of the Earth’s interior. We employ spectral element method incorporated with large-scale parallel computing technology, to investigate the characteristics of seismic wave propagation excited by Wenchuan earthquake. We calculate synthetic seismograms with one-point source model and three-point source model respectively. The AK135 model is employed as a prototype of our numerical global Earth model. The Earth’s ellipticity, Earth’s medium attenuation, and topography data are taken into consideration. These wave propagation processes are simulated by solving three-dimensional elastic wave governing equations. Three-dimensional visualization of our numerical results displays the profile of the seismic wave propagation. The three-point source, which is proposed from the latest investigations through field observation and reverse estimation, can better demonstrate the spatial and temporal characteristics of the source rupture process than the one-point source. We take comparison of synthetic seismograms with observational data recorded at 16 observatory stations. Primary results show that the synthetic seismograms calculated from three-point source agree well with the observations. This can further reveal that the source rupture process of Wenchuan earthquake is a multi-rupture process, which is composed by at least three or more stages of rupture processes. Supported by National Basic Research Program of China (Grant No. 2004CB418406), National Natural Science Foundation of China (Grant Nos. 40774049 and 40474038), and Computer Network Information Center, Chinese Academy of Sciences (Grant No. INF105-SCE-02-12)     

水下岩质边坡稳定性的模型试验研究

随着三峡水利建设工程的进行,许多原本位于水面以上且已趋于稳定的人工或自然岩质边坡将被淹没,导致边坡稳定性降低,而水的压力、冲击、渗流和侵蚀等综合作用,给下岩质边坡的稳定性带来大量的不确定性。基于已有的水下土质边坡稳定性试验和水下岩质边坡有限元分析,进行水下岩质边坡模型试验研究,探讨在水位升降水过程中和波浪作用下水下岩质边坡的稳定性和破坏机制。将结构面为30°和50°的两种岩质边坡模型布置在人工水槽中,采用波流系统进行水位升降水波浪冲击试验,量测岩质边坡的应力变化。通过分析边坡各测点应力变化,得出了一些有意义的结论：（1）把边坡前部岩体划分成3个区域,每个区域内应力变化规律相同;（2）水下岩质边坡坡脚处应力集中最大,破坏始于坡脚,并由此产生的塑性区沿结构面逐渐同坡顶发展,这与一般边坡从坡顶逐渐向下发展的开裂破坏形式完全不同;（3）波浪对水下岩质边坡结构面的影响,将随其倾角的变小而减弱。     

Quantification of spatial gradation of slope positions

Transition between slope positions (e.g., ridge, shoulder slope, back slope, foot slope, and valley) is often gradual. Quantification of spatial transitions or spatial gradations between slope positions can increase the accuracy of terrain parameterization for geographical or ecological modeling, especially for digital soil mapping at a fine scale. Current models for characterizing the spatial gradation of slope positions based on a gridded DEM either focus solely on the parameter space or depend on too many rules defined by topographic attributes, which makes such approaches impractical. The typical locations of a slope position contain the characteristics of the slope position in both parameter space and spatial context. Thus, the spatial gradation of slope positions can be quantified by comparing terrain characteristics (spatial and parametrical) of given locations to those at typical locations. Based on this idea, this paper proposes an approach to quantifying the spatial gradation of slope positions by using typical locations as prototypes. This approach includes two parts: the first is to extract the typical locations of each slope position and treat them as the prototypes of this position; and the second is to compute the similarity between a given location and the prototypes based on both local topographic attributes and spatial context. The new approach characterizes slope position gradation in both the attribute domain (i.e., parameter space) and the spatial domain (i.e., geographic space) in an easy and practicable way. Applications show that the new approach can quantitatively describe spatial gradations among a set of slope positions. Comparison of spatial gradation of A-horizon sand percentages with the quantified spatial gradation of slope positions indicates that the latter reflects slope processes, confirming the effectiveness of the approach. The comparison of a soil subgroup map of the study area with the maximum similarity map derived from the approach also suggests that the quantified spatial gradation of slope position can be used to aid geographical modeling such as digital soil mapping.     

东北地区泥炭表层沉积中植硅体分布特征

表土沉积物中的植硅体分析是了解第四纪沉积物中植硅体组成的重要途径,也是重建第四纪古环境的基础。对东北地区跨越3个气候带、6个地区的41处泥炭地表土中的植硅体进行提取,鉴定出东北泥炭表土中主要发育哑铃型、扇型、鞍型、方型、长方型、梯型、尖型、帽型、齿型、棒型和其它等11种植硅体类型。分析显示,它们的分布与纬度、地形和温热条件具有明显关系,即哑铃型、鞍型、扇型、方型、长方型和梯型植硅体随纬度和海拔较高而含量较小,其余类型反之;较高温度条件对应扇型、哑铃型植硅体含量较高,较高湿度对应扇型植硅体含量较高。     

山西堡子湾金矿床元素地球化学成矿预测研究

堡子湾金矿是华北地台北缘受印支－燕山期线性隐爆角砾岩带控制的金矿床,产于角砾岩体内,产状与角砾岩体基本一致,对该金矿进行了平面,剖面,纵投影面的元素地球化学研究,通过相关分析确定了最佳指示元素,建立了元素地球化学异常模式,进行了回归预测、用与金相关性最好的Ａｓ／Ｎｉ值进行了预测及综合预测,确定了有利的找矿部位。     

建造地下空间的新途径--同步爆扩成型地下空间和混凝土支护层

对于地下空间资源的开发利用,提出了同步爆扩成型地下空间和混凝土支护层的新方法。这一方法也可用于深基坑开挖与支护、地基处理、大面积开挖和地下水防治等岩土工程。     

一种研究城市发展对局地气候要素影响的新方法及其应用

针对气候成因的多样性提出了一种研究城市发展对局地气候要素影响的新方法,该方法采用方差分析和简化分波的手段,尽可能排除非城市发展因素对局地气候要素的影响。利用该方法,研究了合肥城市发展对局地气温的影响。结果表明：城市发展对气温的影响显著,并且主要表现为最低气温的显著增高。     

经济预测模型在土地规划中的应用与分析

主要介绍土地规划时需用到的几种预测模型 ,具体阐述了几种模型的原理 ,并以抚州地区的总人口历史数据为例 ,进行实际的预测与分析 ,从而总结各种模型的优缺点 ,选择最合适的土地规划预测模型。