Assessment of effectiveness of nature reserves on the Tibetan Plateau based on net primary production and the large sample comparison method

Twenty-one typical coupled large samples were chosen from areas within and surrounding nature reserves on the Tibetan Plateau using the large sample comparison method (LSCM). To evaluate the effectiveness of the nature reserves in protecting the ecological environment, the alpine grassland net primary production (NPP) of these coupled samples were compared and the differences between them before and after their establishment as protected areas were analyzed. The results showed that: (1) With respect to the alpine grassland NPP, the ecological and environmental conditions of most nature reserves were more fragile than those of the surrounding areas and also lower than the average values for the Tibetan Plateau. (2) Of the 11 typical nature reserves selected, the positive trend in the NPP for Manzetang was the most significant, whereas there was no obvious trend in Taxkorgan. With the exception of Selincuo, the annual NPP growth rate in the nature reserves covered by alpine meadow and wetland was higher than that in nature reserves consisting of alpine steppe and alpine desert. (3) There were notable findings in 21 typical coupled samples: (a) After the establishment of the nature reserves, the annual rate of increase in the NPP in 76% of samples inside nature reserves and 82% of samples inside national nature reserves was higher than that of the corresponding samples outside nature reserves. (b) The effectiveness of ecological protection of the Mid-Kunlun, Changshagongma, Zoige and Selincuo (Selin Co) nature reserves was significant; the effectiveness of protection was relatively significant in most parts of the Sanjiangyuan and Qiangtang nature reserves, whereas in south-east Manzetang and north Taxkorgan the protection effectiveness was not obvious. (c) The ecological protection effectiveness was significant in nature reserves consisting of alpine meadow, but was weak in nature reserves covered by alpine steppe. This study also shows that the advantage of large sample comparison method in evaluating regional ecology change. Careful design of the samples used, to ensure comparability between the samples, is crucial to the success of this LSCM.     

天然气水合物在油气藏形成过程中的封盖作用——谈造山带中烃源岩对盆地区油气资源的贡献

在中国的造山带中普遍发育优质烃源岩,它们形成于海槽环境,而海槽环境也是形成天然气水合物的有利环境。水合物有良好的封盖作用,其下的油气受到封盖会向相邻的台地区运移,即油气从古海槽区(现今为造山带)向台地区(现今为盆地区)转移。因此造山带中的烃源岩对盆地区油气资源应有积极贡献。认为现今台西南海域的水合物与相邻油气藏具有同源性,这是水合物的封盖作用与油气藏形成之间具有密切联系的生动实例。四川盆地有限的烃源岩分布不能提供巨大的天然气储量,周边造山带可能也提供了相当的资源量。建议在四川盆地和秦岭造山带中系统采集气-液包裹体,以对比它们的亲缘关系,借以验证造山带中的烃源岩是否对盆地区的天然气成藏具有贡献。     

Meta分析在深部找矿预测中的应用——以铜陵铜山铜矿为例

为了深入研究找矿技术方法的优选和集成,引入了"有效性"的概念来衡量某种探测技术方法的找矿预测效果.Meta分析是一种起源于医学领域,对具备特定条件的、同类研究主题的大量研究结果进行综合后统计的超常规综合统计方法.文中对引入Meta分析的思路和可行性充分分析论证后,以铜山铜矿为例,首次应用Meta分析方法对CSAMT,TEM,EH4三种物探方法所获得的二维反演剖面进行了三种方法找矿预测的有效性定量对比研究.结果表明,在铜山铜矿前山南测区,CSAMT法与EH4法的找矿预测有效性比TEM法明显要高;而CSAMT法和EH4法的找矿预测有效性没有明显差异.     

关于来流对槽道推进器流体动力性能影响的研究

作为主动操纵装置的船艏侧推器，其侧推效率受船速的影响会有很大的变化。为能有效地进行操纵控制，本文从理论和实验两方面人手，研究了艏侧推器受船速影响的流体动力性能，并在一定的速度范围内，获得了一种理论估算方法。     

Effectiveness of Cartogram for the Representation of Spatial Data

Abstract

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Cartogram is a technique for visualisation of the geographical distribution of spatial data. It has two main types, i.e. distance cartogram and area cartogram. Area cartogram is a transformed map in which areas are resized in proportion to an attribute value. A number of techniques have been developed for the generation of area cartograms. Some researchers consider cartogram as a very effective technique for visualisation of spatial data, while others doubt about the effectiveness because of the possible distortion in shape and/or disconnectivity in topology. This study aims to evaluate the effectiveness of area cartogram for visualizing spatial data. In this study, two comparative experiments have been conducted. One is the comparison between thematic maps and cartograms, and the other is the comparison among different types of area cartogram. Two sets of data with different characteristics are used, i.e. 2005 China population data and 1996 US election data. Results show that cartogram is more effective in the representation of the 1996 US election data which provides a qualitative result (i.e. in binary form or nominal data), but thematic map is far more effective in the representation of 2005 China population data which provides a quantitative result (in classes or ordinal data). It is also found that among different types of area cartogram, pseudo-cartogram is the most preferred technique and Dorling cartogram is the least preferred one.     

不同覆盖物抑制铀尾矿氡析出的效果

对5种不同覆盖物（红土、砂、废石、砂与红土混合物、废石与红土混合物）降低铀尾矿氡析出的效果进行了现场实验研究。结果表明,不同覆盖物的效果存在较大差异,在相同覆盖厚度条件下,氡析出率降低系数是红土〉红土与废石混合物〉红土与砂混合物〉废石〉砂。表面氡析出率随覆盖物厚度增大而减小,氡析出率降低系数的对数与覆盖厚度成正比,所得到的各种覆盖物的拟合线性方程可用来评价覆盖效果。建立了各种覆盖物覆盖厚度估算的经验公式。综合考虑降氡效果、经济成本、生态环境效应,废石与红土混合物是该地区铀尾矿库最佳覆盖物。     

基于大地形变监测的大震预测问题思考

本文以中国西部大地形变监测与地震预测实践为基础, 简要总结回顾了利用大地形变进行强震预测研究的工作思路、方法和一些进展; 进而结合2001年昆仑山口西8.1级、 2008年四川汶川8.0级特大地震前区域地壳运动变形背景和已有的研究结果, 分析和探讨了基于大地形变监测、 并考虑地震构造的差异性来进一步提高大震预测的有效性...     

基于砂箱物理模拟的断层封闭有效性评价新方法

泥岩涂抹的连续性影响油气跨断层运移,在相似岩性、相似应力条件下,泥岩厚度和断距长度是影响泥岩涂抹连续性的主要因素.本文结合岩芯观察,借助三维定量物理模拟实验对泥岩涂抹的连续有效性进行了研究.结果表明:①泥岩有效涂抹是决定断层封闭性的必要条件,涂抹连续厚度是封闭性评价的重要参数;②受剪切作用在断层带中形成连续的泥岩涂抹油...     

人工洞室上直流电阻率法视电阻率的异常特征

直流电阻率法装置种类较多,根据实际地质条件选用不同的装置类型,通过对探测结果进行综合对比分析,可全面地反映地下洞室赋存状态.通过对一地下人工洞室进行多种装置类型直流电阻率法勘查,综合分析了各种装置类型探测结果的视电阻率异常特征,并论述了直流电阻率法探测地下人工洞室的有效性.     

莺歌海盆地莺东斜坡带隐蔽油气藏类型及成藏主控因素

莺东斜坡带具有“两脊一洼”分段式展布之特殊区域地质构造格局,且自北而南“两脊一洼”三段式分布具有明显不同的构造及断裂活动特征与油气运聚规律,故不同区域区带隐蔽油气藏类型及成藏主控因素差异明显,其中,北段(即北延伸脊)成藏主控因素主要取决于烃源及油气运聚输导系统;中段(一洼即岭头断阶区)成藏主控因素则受控于烃源与岩性圈闭的有效性;南段(南延伸脊)成藏主控因素主要取决于地层岩性复合圈闭的有效性。根据不同类型隐蔽油气藏的成藏主控因素及分布规律,即可采取不同的研究方法及勘探技术对策,以期获得油气勘探的突破。