大气化学研究进展——臭氧、气溶胶研究综述   总被引：2，自引：1，他引：2  

马鹏里 张强杨兴国  王润元 《干旱气象》2003,21(4):66-70

大气化学是大气科学的一门新兴分支学科．早在100多年以前就已开始研究，但是真正发展则以1929年对大气臭氧的观测和对平流层臭氧光化学的理论研究为契机。现阶段大气化学的研究许多事实和现象还不清楚。尤其是关于一些大气微量成分的源、汇和时空分布，它们的迁移、输送和全球循环等问题，都需要进行更加深入广泛的观测和研究。  相似文献   

区域化探异常的地球化学勘查评价方法技术进展综述   总被引：7，自引：1，他引：7       下载免费PDF全文

朱华平  张德全 《地质与勘探》2003,39(3):35-38

区域地球化学异常筛选与评价之地球化学勘查方法技术一直是矿产勘查技术领域的一个热点问题。章回顾了近十几年来区域地球化学异常筛选的方法与思路以及评价异常的勘查地球化学方法的一些进展，并根据不同的覆盖条件和勘查地球化学技术应用条件，把它们分为厚覆盖区勘查地球化学方法技术、基岩区勘查地球化学技术和生物地球化学勘查技术加以评述，最后提出多种地学信息综合集成，尤其是信息科学技术，如地理信息系统、卫星定位系统和遥感技术等互相协作较准确的筛选异常，多学科结合的立体勘查地球化学方法是区域地球化学异常评价以预测隐伏矿床的主要趋势。  相似文献   

TSP超前地质预报在圆梁山隧道施工中的应用   总被引：13，自引：0，他引：13  

朱宝龙  陈强  魏有仪  王鹰 《水文地质工程地质》2003,30(1):81-83,90

介绍了TSP超前地质预报系统的技术特点和基本测量原理，结合渝（重庆）怀（化）线圆梁山隧道的实例，将TSP系统和超前地质钻孔预报结果进行对比，显示了该系统的实用性。  相似文献   

地球的起源与演化研究进展   总被引：3，自引：2，他引：3  

叶玉江  吴淦国  张达 《现代地质》2003,17(2):119-124

地球科学在研究远古地球的形成与演化方面积累了越来越多的证据 ,人类对于太空的观测程度也不断提高 ,加深了对类地行星的认识 ,取得了重要的成果。太阳系中的火星和金星可能存在已经绝灭了的生命。慧星和小行星对地球的多次撞击有能力导致严重的环境效应及生命大灭绝。行星的演化可能有两种模式 :冷的星团加热及热的星云冷却。火星上存在与地球壳体非常相似的沉积岩 ,说明有流动水存在的可能。较高地热的太古代地壳热流输出被认为是认识地壳构造特性的关键。晚太古代会聚与离散大陆边缘的对比研究表明太古代板块运动与年轻的板块构造旋回在样式及幕次方面都没有根本的区别。元古代大陆的增生是由于元古代源于地幔的板块构造及产生于地幔的热柱构造导致新生成分的加入而造成的。裂谷、盆地、推覆及伸展、火山侵入作用是显生宙大陆增生的主要因素。  相似文献   

Influence of Rock Mass Parameters on the Performance of a TBM in a Gneissic Formation (Varzo Tunnel)   总被引：4，自引：1，他引：4  

R. Ribacchi  A. Lembo Fazio 《Rock Mechanics and Rock Engineering》2005,38(2):105-127

Summary The paper analyses the influence of rock mass quality on the performance of a double shield TBM in the excavation of a tunnel in a gneiss formation which is characterized by high strength and low fracture intensity.As full observation of the rock conditions was prevented by the use of segmental lining, a geomechanical survey of the face was performed during maintenance downtime and the observed conditions were correlated with the machine performance parameters for that same day. A statistical analysis of the data shows that penetration rate correlates well with a slightly modified RMR index (in which the influence of the water conditions and joint orientation were discounted), but the most important factor is by far the partial rating of the RMR classification related to joint spacing only. However in tunnels characterized by greater variability in rock strength and joint conditions, it could be worthwhile using the complete RMR index.Given the toughness of the rock, failure of the cutter bearings and supports were a frequent occurrence during excavation. Owing to this factor the influence of rock quality on the rate of advance was found to be weak and the correlation more scattered.The results obtained for the Varzo tunnel were compared with those relative to other tunnels in granitic rocks and found to be in good agreement. However the relationships obtained should be considered valid only for this type of rock; machine behaviour could be found to be markedly different in other rock types, even where rock material strength and joint frequency are the same.  相似文献   

国外大气沉降泥炭沼泽档案研究进展   总被引：3，自引：3，他引：3  

王国平  贾琳  刘景双  王金达 《湿地科学》2006,4(1):69-74

雨养泥炭沼泽养分补给主要源于大气降水。因为沼泽表面水的流动是缓慢并且有限的,所以沉降至其中的物质依然基本保留在原处。因此,大气颗粒物污染历史在泥炭累积时被保存。在最近20a期间,雨养泥炭沼泽被证明是痕量元素大气沉降富有意义的档案。尤其Pb被广泛深入地研究,并且Pb在泥炭芯中的非迁移性被很好地展示,其它元素也被指明保存在泥炭芯中。国外的泥炭沼泽沉积记录研究在某些方面非常深入细致,前期工作成为后续工作的铺垫,长年的积累形成一定的系统性。利用泥炭沼泽档案,人们对历史时期的环境研究取得了一定成果,尤其在大气金属沉降的泥炭沼泽档案与泥炭地古气候反演方面;但稍显不足的是比较重视对“记录”的研究,而对“机制”的研究深度不够。  相似文献   

干旱、半干旱区陆气相互作用的研究进展   总被引：5，自引：10，他引：5  

鲍艳  吕世华 《中国沙漠》2006,26(3):454-460

 对干旱、半干旱地区陆气相互作用的研究进展及发展现状做了总结，并结合近年来在干旱、半干旱地区开展的近10个有关陆气相互作用的大型野外观测试验和具有代表性的土壤水热参数化方案，分析了当前干旱区陆面过程研究中存在的问题，最后探讨了干旱区陆面过程未来的发展趋势。  相似文献   

Stress Changes due to Recent Seismic Events in the Central Apennines (Italy)     

Andrea?Tallarico  Stefano?SantiniEmail author  Michele?Dragoni 《Pure and Applied Geophysics》2005,162(12):2273-2298

The Central Apennines, Italy, are characterized by moderate seismic activity on normal faults, oriented in directions parallel to the Apenninic chain. The subject of this study is the Umbria-Marche Apennines, a segment approximately 200-km long, where three main seismic events occurred in the last three decades. The 1979 Norcia earthquake was a M_w = 5.8 event, taking place at the south end of the considered segment. The 1984 Gubbio earthquake was a M_w = 5.6 event which took place at the north end. The 1997-1998 Colfiorito sequence constituted 8 main shocks with magnitudes M_w between 5 and 6 and epicenters located between the Gubbio and the Norcia earthquake areas. A model made of an elastic half-space is considered, in which the seismic sources are represented by rectangular dislocations which have the appropriate values of source parameters, and in which the static stress field produced by each event is calculated. The analysis of the Coulomb stress change (ΔC) as a function of time shows that the coseismic stress transfer and fault interaction played an important role in the region during the past three decades: 7 earthquakes of the 9 considered took place where ΔC>0. Such an interaction has been confirmed by the analysis of the aftershocks in the Colfiorito zone post September 26, 1997: about the 61% of the aftershocks considered took place where ΔC>0. The comparison between the ΔC^s due to the coseismic stress transfer and the rate ΔĊ^t due to the tectonic stress allows us to quantify the time advance of the earthquakes. The ΔC^s pattern shows positive values in two areas that can be regarded as historical seismic gaps.  相似文献   

组合逻辑自动综合的超前试探法     

邓德祥  李玉林  钟诚东 《武汉大学学报(信息科学版)》1997,(2)

自动逻辑综合是复杂组合电路设计中必须面对的问题之一。本文采用超前试探策略，在改进的Ｑ－Ｍ法基础上，提出了一个新的组合自动综合的新算法，该算法提高了运算速度，有较强的实用价值  相似文献   

异黄酮的合成研究进展   总被引：4，自引：0，他引：4  

陈中胜  黄国林 《华东地质学院学报》2002,25(1):62-65,87

综述了异黄酮合成方法和近年来我国在合成异黄酮化合物的研究进展。  相似文献