物化探方法在寻找深部硫化铜矿中的应用——以赞比亚麻希巴矿床为例

物化探方法寻找隐伏矿床在国内外已得到广泛应用,赞比亚麻希巴矿床属卢弗利安穹隆构造成矿带上一典型层控矿床,赋矿层位为下罗恩群RL6泥岩片岩下部和RL7砂砾岩上部,矿体从浅至深具有氧化带-硫化带过度特点。为探索深部硫化铜矿体延伸情况,本文利用地球物理(激电极化法、高密度电阻率法和音频大地电磁法)和地球化学方法(土壤测量、偏提取测量),选择三条剖面进行物化探方法对比研究,物探结果显示硫化矿具有低阻(50～300Ω·m)、高幅频率(2.5%～8.0%)异常特征,高密度电阻率法和音频大地电磁法的电阻率等值线能较清晰地反映基底和RL7底部不含矿地层形态变化,对找矿有良好的指示作用;化探结果显示Cu元素相关元素为Ag、Bi,在沉积成矿过程中形成Cu-Ag-Bi元素组合,在近地表氧化矿呈"驼峰"高值异常,在深部硫化矿上方呈"偏锋"弱异常,偏提取显示Cu、Co、Bi元素主要是以第二相形式存在,在深部硫化矿上方呈"多锋"弱异常。在方法有效性试验结果的基础上,总结和建立了该矿床类型的地、物、化综合找矿模型,依据物化探异常圈定了深部找矿靶区,经后期钻探工程验证见到两层工业矿体,取得了较好的找矿效果。激电极化法...     

GStar-Ⅰ型电容式土壤水分监测仪设计与应用

介绍了河南省气象科学研究所研制的GStar-I型电容式土壤水分测量仪的测量原理、特性和设计思路,以及振荡电路、分频电路、嵌入式单片机、计算机通讯技术和软件系统设计,并对其标定方法进行了探讨.该仪器在河南、陕西等省进行了安装试用,能够实时连续自动采集土壤水分数据、记录各地土壤水分的变化规律.应用实践表明,该传感器具有使用简单安全,定点连续,易于标定,精度较高等特点.     

Coherent modes in multi‐scale variability of precipitation over the headwater catchments in the Pearl River basin,South China

This paper studies the coherent modes of multi‐scale variability of precipitation over the headwater catchments in the Pearl River basin in South China. Long‐term (1952–2000) daily precipitation data spatially averaged for 16 catchments in the basin are studied. Wavelet transform analysis is performed to capture the fluctuation embedded in the time series at different temporal timescales ranging from 6 days to 8.4 years. The catchment clusters of the coherent modes are delineated using the principal component analysis on the wavelet spectra of precipitation. The results suggest that as much as 98% of the precipitation variability is explained by only two coherent modes: high small‐scale mode and high seasonal mode. The results also indicate that a large majority of the catchments (i.e., 15 out of 16) exhibit consistent mode feature on multi‐scale variability throughout three sub‐periods studied (1952–1968, 1969–1984, and 1985–2000). The underlying effects of the coherent modes on the regional flood and drought tendency are also discussed.     

川主寺—黄龙左行走滑剪切断层和松潘—平武剪切转换构造体制

石炭系碳酸盐岩中大规模断层崖残留体是研究区新构造变动的显著地貌特征。相关摩擦滑动面的产状、擦痕线理定向及其运动学标志的野外观测数据表明,西起川主寺,东抵黄龙乡,中更新世(Q2)以来存在一条近东西走向的左行走滑断层。沿川主寺—黄龙左行走滑断层的位移在切错了近SN走向的岷山隆起后,向东追踪并改造先存的雪山逆冲断层,在黄龙乡以东通过3种方式发生了构造和位移转换,即(1)其前方北侧派生出一系列NE走向的左行剪切断裂;(2)沿走向位移逐渐减弱为顺层滑动;(3)其前方南侧转化为沿近SN向虎牙断裂的左旋斜冲。川主寺—黄龙断裂的构造几何学和运动学特征及其与岷江、虎牙冲断层的构造联系,支持一个左行剪切转换构造体制。松潘—平武地区的卫星遥感图像,1970—2008年的地震活动性,以及1991年以来4次GPS重复测量结果所建立的现今位移矢量场等证据表明,川主寺—黄龙左行走滑断裂系统是继东昆仑—岷江断裂组合之后发育起来的、现在仍然活动的剪切转换断裂构造,是青藏高原东缘东北角的典型地震构造样式之一,反映了青藏高原物质具有向东逃逸的趋势。     

岩土工程勘察的风险控制

岩土工程勘察存在着岩土自身和人的认知程度两方面的不确定性,主要的风险控制管理点在于解决这两个不确定性的问题上。再加上认真执行有关规范就可将岩土工程勘查控制在可以接受的范围之内。     

北京通州区某会馆基坑液化地基处理

北京通州区某会馆基坑底为饱和粉细砂并夹有淤泥,非常软弱,现场标贯试验判断基坑以下5m范围内为中等—严重的液化土,建议采用碎石桩法进行处理。但由于施工区基坑狭小、侧壁陡直,且地下管线密布,碎石桩难以施工。在准确验证场地液化层厚度的基础上,采用了静压注浆法来处理该液化地基,并用瑞利波法检测注浆前后的场地等效平均波速。检验结果显示,注浆后的场地等效平均波速高于140m/s,说明该处理方法达到了消除地基液化的目的。     

Seasonal variation in carbon exchange and its ecological analysis over <Emphasis Type="Italic">Leymus chinensis</Emphasis> steppe in Inner Mongolia

Eddy covariance technique was used to measure carbon flux during two growing seasons in 2003 and 2004 over typical steppe in the Inner Mongolia Plateau, China. The results showed that there were two different CO₂ flux diurnal patterns at the grassland ecosystem. One had a dual peak in diurnal course of CO₂ fluxes with a depression of CO₂ flux after noon, and the other had a single peak. In 2003, the maximum diurnal uptake and emitting value of CO₂ were ?7.4 and 5.4 g·m^?2·d^?1 respectively and both occurred in July. While in 2004, the maximum diurnal uptake and release of CO₂ were ?12.8 and 5.8 g·m^?2·d^?1 and occurred both in August. The grassland fixed 294.66 and 467.46 g CO₂·m^?2 in 2003 and 2004, and released 333.14 and 437.17 g CO₂·m^?2 in 2003 and 2004, respectively from May to September. Water availability and photosynthetic active radiation (PAR) are two important factors of controlling CO₂ flux. Consecutive precipitation can cause reduction in the ability of ecosystem carbon exchange. Under favorable soil water conditions, daytime CO₂ flux is dependent on PAR. CO₂ flux, under soil water stress conditions, is obviously less than those under favorable soil water conditions, and there is a light saturation phenomena at PAR=1200 μmol·m^?2·s^?1. Soil respiration was temperature dependent when there was no soil water stress; otherwise, this response became accumulatively decoupled from soil temperature.     

西北地区退耕还林对区域气候的影响

利用NCEP再分析资料对2009年3月20日夜至21日凌晨豫北强对流天气过程进行了分析,结果表明：①导致这次强对流天气发生的湿位涡场分布特征为,对流层低层MPV1〉0,同时MPV2〈0;强对流发生时,对流高层表现为MPV1〉0,同时MPV2〈0,即高低层均为异常的湿对流稳定区。②强对流的发生发展与湿位涡的时空演变有着很好的对应关系,对流层高低层湿位涡“正负区垂直叠加”的配置是强对流天气发展的有利形势。这次强对流天气发生在低层湿位涡正压项等值线密集的零线附近以及大于零的区域和湿位涡斜压项的负值区,同时高层为湿位涡正压项等值线密集正值区域和湿位涡斜压项的负值区。③中低层急流和地面东路冷空气入侵高温高湿不稳定区是形成这次强对流天气的主要原因,中尺度对流云团是造成此次强对流天气的直接影响系统,且强对流发生前,近地面存在逆温层。     

2010年我国南方两次持续性强降水的环流特征

通过对2010年夏季我国南方两次持续性强降水期间对流层高、中、低多个大尺度关键影响系统的时空演变特征及其影响机制的分析和比较,讨论了我国南方持续性强降水的大气环流特征。结果表明:这两次持续性强降水均出现了东亚西风带沿海低槽不断快速重建或加深,且中纬度锋区位置稳定维持,低空西南急流反复加强,且其轴线左侧的南风经向强梯度带位置相对稳定,副热带高空西风急流和南亚高压脊线及西太平洋副热带高压的纬度带位置相对稳定;相应地,在强降水带上空反复出现强烈的低层水汽辐合抬升、高层辐散抽吸及垂直上升运动发展,进而形成持续性强降水。西西伯利亚低槽的不断快速重建与加深 (东移)、马斯克林高压西侧高压及马斯克林高压的不断加强东移、副热带高空西风急流的建立和维持对南方持续性强降水具有超前指示意义。强降水带位于东亚低空西南急流轴左侧南风经向强梯度辐合带、高空西风急流南侧至南亚高压脊线北侧之间的强辐散区及中层垂直上升速度大值带中。     

PM2.5监测及评价研究进展

综合阐述了近年来国内外PM2.5的监测方法、观测站网建设发展,以及PM2.5对人体健康、大气环境及天气、气候等方面的影响研究,并对国内外PM2.5空气质量标准差异进行了比较分析,提出了加强PM2.5监测及影响评价的建议。