南极中山站石榴石变粒岩的岩石学矿物学及其变质作用研究

本文报道了南极拉丝曼丘陵“中山站”石榴石变粒岩的岩石学和矿物化学特征;确定了其矿物组合及世代演化关系,利用电子探针分析了其特征变质矿物的化学组成,最后推断东南极拉丝曼丘陵地区曾发生过麻粒岩相变质作用和混合岩化作用。     

Primary productivity in the western tropical Pacific and equatorial warm waters

ＩＮＴＲＯＤＵＣＴＩＯＮＢｙｓｔｕｄｙｉｎｇｃｈｌｏｒｏｐｈｙｌｌａｎｄｐｒｉｍａｒｙｐｒｏｄｕｃｔｉｖｉｔｙｉｎｏｃｅａｎ ,ｅｉｔｈｅｒｉｎｔｈｅｂｉｇ ｓｃａｌｅｏｒｉｎｔｈｅｓｍａｌｌｓｃａｌｅ ,ｔｈｅｐｒｏｄｕｃｔｉｖｉｔｙｄｉｓｔｒｉｂｕｔｉｏｎａｎｄｖａｒｉａｔｉｏｎｏｆｍａｒｉｎｅｏｒｇａｎｉｃｍａｔｅｒｉａｌｉｎｔｈｅｔｅｍｐｏ ｒａｌａｎｄｓｐａｔｉａｌｃａｎｂｅｕｎｄｅｒｓｔｏｏｄ .Ｔｈｅｓｅａａｒｅａｓ ,ｓｉｔｕａｔｉｎｇｉｎｔｈｅｗｅｓｔｅｒｎｔｒｏｐｉｃａｌＰａｃｉｆｉｃ…     

滇西地区地壳上地幔电性结构与地壳构造活动的关系

本文根据滇西地区18个大地电磁测深点资料的数据处理和分析结果,对测区深部导电率在纵、横向上的变化特征进行了研究。结果表明:滇西地区深部电性为多层结构,大致可分四至五个电性结构层;深部电性结构横向变化大,明显受区域构造控制;该区上部地壳内普遍存在低阻层;上地幔高导层明显存在两个隆起区,一个以剑川—鹤庆为中心呈北北西向展布的隆起区,另一个以腾冲—潞西为轴呈南北向展布的隆起区。 本文还讨论了地壳上地幔电性结构与大地构造的关系,滇西北裂陷区盆地的形成,以及该区地震活动与深部构造的关系     

北京市地铁暗挖施工沉降控制探讨

仅以北京市地铁4#线张自忠车站主体暗挖施工的沉降监控项目为研究背景,对穿越城市主干道的车站结构暗挖施工进行连续性的沉降变形监测;从地下构筑物暗挖施工的工序变化与地表沉降的关系进行试验研究.在预测基础上对获取的数据进行多层次的统计与分析,以研究其变形规律与稳定性,实现了信息化施工.     

框架预应力锚杆边坡支护结构的稳定性分析方法及其 应用

以边坡极限平衡理论及框架预应力锚杆边坡支护结构的圆弧滑动破坏模式为基础,在考虑框架、锚杆对土体边坡稳定性影响的情况下,基于圆弧滑动条分法的思想利用积分法建立了内部稳定性安全系数计算模型和最危险滑移面搜索模型。确定滑移面圆心坐标为几何控制参数,推导了安全系数计算模型中各变量与滑移面圆心坐标之间的函数关系式,从而获得了滑移面几何控制参数与内部稳定性安全系数之间的函数关系。利用网格法对框架预应力锚杆支护结构最危险滑移面的圆心坐标进行动态搜索和求解。最后采用Matlab语言编制了框架预应力锚杆边坡支护结构的稳定性分析程序,并结合工程实例进行了验算,讨论了此种方法的适用条件,结果表明该方法简明适用,较传统的经验分析方法更加合理。     

Preserved paleo-oceanic plateaus in accretionary complexes: Implications for the contributions of the Pacific superplume to global environmental change

We have reinvestigated the mid-Cretaceous plume pulse in relation to paleo-oceanic plateaus from accretionary prisms in the circum-Pacific region, and we have correlated the Pacific superplume activity with catastrophic environmental changes since the Neoproterozoic. The Paleo-oceanic plateaus are dated at 75–150 Ma; they were generated in the Pacific superplume region and are preserved in accretionary prisms. The volcanic edifice composed of both modern and paleo-oceanic plateaus is up to 10.7 × 10⁶ km² in area and 19.1 × 10⁷ km³ in volume. The degassing rate of CO₂ (0.82 − 1.1 × 10¹⁸ mol/m.y.) suggests a significant impact on Cretaceous global warming. The synchronous occurrence of paleo-oceanic plateaus in accretionary complexes indicates that Pacific superplume pulse activities roughly coincided at the Permo-Triassic boundary and the Vendian–Cambrian boundary interval. The CO₂ expelled by the Pacific superplume probably contributed to environmental catastrophes. The initiation of the Pacific superplume contributed to the snowball Earth event near the Vendian–Cambrian boundary; this was one of the most dramatic events in Earth's history. The scale of the Pacific superplume activity roughly corresponds to the scale of drastic environmental change.     

《中国21世纪议程》与西北持续发展

本文概要介绍了我国２１世纪发展白皮－《中国２１世纪议程》;全面列举了国际社会对西北地区第一批优先项目支持的承诺,勾勒了西北地区“可持续发展之路”的轮廓。     

坡地农林复合系统的结构类型与效益分析─以长江三峡库区坡地农业为例

本义认为现代术语的农林复合系统来源于生产实践,体现了农业与林业的有机结合、品种生态和经济的有机结合、产品多样化以及管理科学化4个方面相统一的特点。文章在分析三峡库区农林复合系统的类型结构基础上,提出了农林复合系统可以进行层次结构划分的观点。最后,以典型案例研究方法入手,对1种农林结构类型进行效益分析,结果表明,采用植物篱农林复合坡地系统,是现阶段生产力水平下实现坡地生态经济协调发展的有效途径,值得广泛推广。     

Hamiltonian perturbation theory on a manifold

This paper deals with Hamiltonian perturbation theory for systems which, like Euler-Poinsot (the rigid body with a fixed point and no torques), are degenerate and do not possess a global system of action-angle coordinates. It turns out that the usual methods of perturbation theory, which are essentially local being based on the construction of normal forms within the domain of a local coordinate system, are not immediately usable to study perturbations of these systems, since degeneracy makes impossible to control that the system does not fall into a singularity of the coordinates. To overcome this difficulty, we develop a global formulation of Hamiltonian perturbation theory, in which the normal forms are globally defined on the phase space manifold. The key for this study lies in the geometry of the fibration by the invariant tori of an integrable degenerate Hamiltonian system, which is described by some generalizations of the Liouville-Arnol'd theorem and is reviewed in the paper. As an application, we provide a global formulation of Nekhoroshev's theorem on the stability for exponentially long times.