苏里格庙地区凝灰质溶蚀作用及其对煤成气储层的影响

苏里格庙地区二叠系煤成气储层非均质性明显,次生孔隙发育,砂岩中含有大量不稳定凝灰质填隙物。溶蚀模拟实验表明,在酸性水环境中,凝灰质填隙物发生明显溶蚀,并且酸性介质浓度越高溶蚀作用越强烈。在有残余粒间孔隙或裂缝沟通的较开放环境里凝灰质填隙物溶蚀作用强烈;而在较封闭的环境中,溶蚀作用不能充分进行,凝灰质填隙物保存较好。凝灰质填隙物溶蚀产生的次生孔隙,改善了煤成气储层的储集性能;但由于异地胶结作用,又在一定程度上损害了煤成气储层的整体连通性,这是鄂尔多斯盆地二叠系煤成气储层强非均质性和低渗透性的根本原因。     

陕西龙门山地震带地质灾害的地质构造约束

汶川8级特大地震发生于龙门山地震带,地震灾害损失惨重,震后诱发大量次生山地地质灾害。通过笔者参加的我省宁强、略阳等县汶川震后次生地质灾害应急排查,结合区域地质、控震构造和地震活动性分析,以期对陕西龙门山地震带次生山地地质灾害特点和地震活动规律的探讨,对我省防灾减灾提供有益的帮助。     

Secondary Silicates as a Barrier to Carbon Capture and Storage in Deccan Basalt

Investigating the immobilization of CO2, previous basalt-water-CO2 interaction studies revealed the formation of carbonates over a short period, but with the extensive formation of secondary silicates (SS). The mechanisms involved in these processes remain unresolved, so the present study was undertaken to understand secondary mineral formation mechanisms. XRPD and Rietveld refinement data for neo-formed minerals show a drastic decrease in the Ca-O bond length, with the calcite structure degenerating after 80 h (hours). However, SEM images and EDS data revealed that a longer interaction time resulted in the formation of chlorite and smectite, adjacent to basalt grains which prevent basalt-water-CO2 interaction to form carbonates, thus restricting carbonate formation. As a result of this, the CO2 mineralization rate is initially high (till 80 h), but it later reduces drastically. It is evident that, for such temperature-controlled transformations, low temperature is conducive to minimizing SS surface coating at the time of mineral carbonation.     

Do young martian ray craters have ages consistent with the crater count system?

McEwen et al. (McEwen, A.S., Preblich, B.S., Turtle, E.P., Artemieva, N.A., Golombek, M.P., Hurst, M., Kirk, R.L., Burr, D.M., Christensen, P. [2005]. Icarus 176, 351-381) developed a useful test for the internal consistency of crater-count chronometry systems. They argued that certain multi-kilometer, fresh-looking martian craters with prominent rays should be the youngest or near-youngest craters in their size range. The “McEwen et al. test” is that the ages determined from crater densities of the smallest superimposed craters (typically diameter D ∼ 5-20 m) should thus be comparable to the expected formation intervals of the host primary. McEwen et al. concluded from MOC data that crater chronometry failed this test by factors of 700-2000. We apply HiRISE and other imagery to eight different young craters in order to re-evaluate their arguments. We use existing crater chronology systems as well as the reported observed production rate of 16 m craters (Malin, M.C., Edgett, K., Posiolova, L., McColley, S., Noe Dobrea, E. [2006]. Science 314, 1573-1557; Hartmann, W.K., Quantin, C., Mangold, N. [2007]. Icarus 186, 11-23; Kreslavsky [2007]. Seventh International Conference on Mars, 3325). Every case passes the McEwen et al. test. We conclude that the huge inconsistencies suggested by McEwen et al. are spurious. Many of these craters show evidence of impact into ice-rich material, and appear to have ice-flow features and sublimation pits on their floors. As production rate data improve, decameter-scale craters will provide a valuable way of dating these young martian geological formations and the processes that modify them.     

关中平原大地等效电导率的间接测量

为准确预报地波传播时延,用电波传播法对关中平原的大地等效电导率进行了间接测量。阐述了电波传播法的测量原理和方法,第一次给出关中平原大地等效电导率的间接测量结果,同时,给出了中国科学院国家授时中心临潼科研楼参考点的BPL信号传播时延测量结果,并对这些测量结果进行了精度分析。     

矿区地表移动变形监测数据处理

本文采用AutoCAD VBA二次开发技术,实现了地表移动观测数据处理、成图自动一体化.克服了传统方法成图只能查看、不易定量分析的缺点;在输出下沉、倾斜、曲率、水平移动、水平变形计算结果的同时,将各移动变形曲线和对应的地下煤层开采情况按一定比例尺在CAD中成图.可实现从图中曲线上直接量取任意点的对应值;较方便地从图中求...     

咸宁核电厂首批次级测量控制网的建立及分析

介绍了咸宁核电厂次级网设计的原则及实施过程中的注意事项,分析了采用GPS静态定位方式下的数据观测、数据处理控制方法,对GPS基线边长质量控制采用高精度全站仪进行了边长观测比较分析。     

Curricular Changes in the Teaching of Geography in Swiss Upper Secondary Schools: An Attempt to Develop Skills for Lifelong Learning

Abstract

This article is an overview of the curriculum reform in Switzerland in the 1990s. It describes the grass-roots reform process in geography education in upper secondary schools and its impact on the development of new teaching materials. These ancillary materials are based on teaching methods and strategies, the effectiveness of which are empirically shown by results. The teaching units complement the thematic and methodological aims in the national curriculum and the federal regulations and were designed through a partnership of teachers, teacher educators and scientists. They can be translated directly into the practice of teaching and are available free to teachers through the World Wide Web.     

Changing Perspectives in High School World Geography: 1950–2005

Abstract

This study set out to better understand the changing links between geography and citizenship. Content analysis was conducted on eighteen high school world geography textbooks and state/national standards. Interviews were conducted with teachers and textbook authors. Five significant changes were noted: decline of national orientation and a greater focus on non-Western cultures; greater emphasis upon consumption over production; the accentuation of values clarification; increasing coverage of basic or prevocational skills; and standardization of format and content in textbooks. Many of these changes point towards a new cosmopolitan citizenship model, although some teachers and state social studies standards still see geography from a national perspective.     

Observational Work for Children

Abstract

Geographic information systems (GIS) are computer-based tools for geographic data analysis and spatial visualization. They have become one of the information and communications technologies for education at all levels. This article reviews the current status of GIS in schools, analyzes the requirements of a GIS-based learning environment from constructivist perspectives, and discusses the major issues in the design of a constructivist GIS-based learning environment based on experience from the development of World Explorer, a GIS-based learning environment that provides a theme-oriented data and information base, supports multiple representations and multiple linkages of information, and facilitates interactive learning and knowledge construction.