柯坪6.5级地震的部分前兆异常及预报

1991年2月25日柯坪6.5级地震前,震中附近地区的土层地应力、金属摆倾斜仪等多项前兆观测出现异常变化,说明强震发生前近场灵敏度较低的简陋仪器也能观测到明显的前兆反应。分析、认识这些异常对地震短临预报的决策是有益的。     

南极GPS数据质量分析

以多路径误差和电离层延迟为评价指标,利用TEQC软件和QCVIEW软件对南极埃默里冰架、内陆冰盖、纳拉峡海湾、拉斯曼丘陵的实测GPS数据以及部分IGS站点的数据进行了数据质量分析,得到结论： 1)在同一站点上,L2上的多路径误差总比L1上的多路径误差要大;2)在南极不同环境下的多路径误差不同;3)纬度和太阳活动剧烈程度是影响南极地区GPS数据电离层延迟大小的两个重要因素。     

“95.8”川西大暴雨成因分析

通过对“９５．８”大暴雨过程的全面技术总结，揭示了多种尺度系统间相互作用对产生大暴雨过程的贡献，并指出了云团的发生及其发展源于北方冷空气和南方低空急流持续影响所形成的两个中间尺度垂直环流。     

Effect of Shale Reservoir Characteristics on Shale Oil Movability in the Lower Third Member of the Shahejie Formation,Zhanhua Sag

To reveal the effect of shale reservoir characteristics on the movability of shale oil and its action mechanism in the lower third member of the Shahejie Formation(Es3l), samples with different features were selected and analyzed using N2 adsorption, high-pressure mercury injection capillary pressure(MICP), nuclear magnetic resonance(NMR), high-speed centrifugation, and displacement image techniques. The results show that shale pore structure characteristics control shale oil movability directly. Movable oil saturation has a positive relationship with pore volume for radius > 2 μm, as larger pores often have higher movable oil saturation, indicating that movable oil is present in relatively larger pores. The main reasons for this are as follows. The relatively smaller pores often have oil-wetting properties because of organic matter, which has an unfavorable effect on the flow of oil, while the relatively larger pores are often wetted by water, which is helpful to shale oil movability. The rich surface provided by the relatively smaller pores is beneficial to the adsorption of immovable oil. Meanwhile, the relatively larger pores create significant pore volume for movable oil. Moreover, the larger pores often have good pore connectivity. Pores and fractures are interconnected to form a complex fracture network, which provides a good permeability channel for shale oil flow. The smaller pores are mostly distributed separately;thus, they are not conducive to the flow of shale oil. The mineral composition and fabric macroscopically affect the movability of shale oil. Calcite plays an active role in shale oil movability by increasing the brittleness of shale and is more likely to form micro-cracks under the same stress background. Clay does not utilize shale oil flow because of its large specific surface area and its block effect. The bedding structure increases the large-scale storage space and improves the connectivity of pores at different scales, which is conducive to the movability of shale oil.     

粗差验后方差的无偏估计与最优稳健估计

在正态粗差假设下导出了粗差验后方差的无偏估计,对误差工膨胀模型和误差均值移动模型,两者的无偏估计公式是相同的。这证明了李德仁验后方差的朱建军方差不是无偏的。由于偏方定义的彭方法是正态粗差假设下的最优稳健估计。     

Axisymmetry in protoplanetary nebulae – II. A near-infrared imaging polarimetric survey

In an imaging polarimetry survey of candidate post-AGB stars, scattering envelopes are detected around 20 objects. These envelopes represent the final mass-loss phases at the end of the AGB. In all cases, evidence for axisymmetry in the dust density is seen, suggesting that the presence of an axisymmetric outflow may be a ubiquitous phenomenon of the AGB to post-AGB transition. We use the polarized flux images to classify the objects into detached shell, bipolar and unresolved targets. Modelling based on a simple axisymmetric shell geometry supports the contention that post-AGB objects fall into one of two classes that differ in the amount of dust in the circumstellar environment: the detached shells correspond to stars with an optically thin expanding circumstellar envelope (CSE) whereas the bipolar and unresolved targets have optically thick dust structures, probably in the form of discs, which remain bound to the star, rather than partaking in the expansion of the AGB CSE. It is suggested that this bifurcation in morphology is rooted in the presence or absence of a binary companion, which determines whether or not a disc forms. Because the detached shell objects also appear axisymmetric, an additional mechanism for generating the axisymmetry, such as a magnetically shaped outflow, is needed if they do indeed have single star progenitors.     

山东沂水杂岩中变基性岩的岩石地球化学特征及锆石SHRIMP U-Pb定年

山东沂水杂岩由新太古代岩浆杂岩和中太古代的变质杂岩组成,其后者中的变基性岩石,特别是基性麻粒岩,常与紫苏花岗岩紧密伴生,而且多呈大小不等的包体或呈层状体产出。本文主要对变基性岩进行岩石地球化学和锆石SHRIMP UPb定年研究。根据岩石学特征,可将变基性岩分为三类：含紫苏辉石斜长角闪岩、含石榴子石角闪二辉斜长麻粒岩和含尖晶石—石榴子石的角闪二辉麻粒岩。它们原岩分别为安山质玄武岩、高铁镁质玄武岩和玄武质科马提岩（？）。三类岩石稀土元素和微量元素配分有一定差别：第一类含紫苏辉石斜长角闪岩富集轻稀土和大离子亲石元素,亏损Nb、Ta、Zr、Hf等高场强元素;后二类麻粒岩相变质岩的稀土配分模式为近平坦型或轻稀土略为富集, K、Rb、Ba等元素也轻微富集,其他元素与MORB的比值接近于1。变基性岩中锆石定年结果显示有四组年龄值,其中2719Ma和2560～2607Ma分别代表早期麻粒岩相变质作用的年龄下限和上限;2509～2522Ma代表另一期角闪岩相—麻粒岩相变质作用的时代,发生在沂水岩浆杂岩侵入之后;2485Ma和2497Ma代表与流体作用有关的变质作用和新生锆石的形成年龄。     

中国中央造山带资源环境态势与可持续发展对策

资源与环境是谋求发展的物质基础和重要前提,其合理开发利用是实现可持续发展的重要内容。中国中央造山带富能、富矿、少植被、土地瘠薄,这对该区的经济发展既显示了无穷的诱惑,却又制约着对其的开发利用。对此,从保护利用水土资源、利用资源优势促进经济发展以及发展科技教育与提高人口素质三方面提出建议以促进该区走上可持续发展之路。     

岩溶洞穴次生碳酸盐沉积铀及其同位素组成古气候环境研究进展

洞穴沉积铀含量及其同位素初始234U/238U[（234U/238U)0]变化均与过去气候环境变化关系密切。文章分别对石笋中U含量和(234U/238U)0的气候意义进行统计分析发现,多数研究认为洞穴沉积U含量和(234U/238U)0可能指示土壤湿度和有效降水变化。然而,不管是对洞穴沉积的U含量还是(234U/238U)0,其气候环境意义解读还存在两种观点。但无论如何,这些研究成果都显示了洞穴沉积的U含量和(234U/238U)0是研究过去气候环境变化的重要替代指标。在未来的研究中,除了土壤环境和过程,还应关注U来源的相对贡献变化和其他微量元素与U元素的关系。这一指标可能在对东亚地区的大气粉尘活动和冬季风演化、地表生物量的变化研究等方面发挥重要作用。      

近50年气候变化对滦河上游径流的影响

为了解近50年滦河上游气温和降水气候的变化特征、趋势及其对该流域径流量的影响,利用1956-2009年滦河上游的实测气温、降水量和径流深资料,分析了该流域气温、降水和径流深的年均和季度变化的时间序列,并建立了该流域气候变化对径流影响的复相关回归模型。结果表明,年径流深随着年降水量的减少而减少,随着年平均气温的升高而减少;春、夏和秋季的径流深随着同期降水量和气温的变化趋势与年际变化趋势基本一致,但冬季径流深则相反,而且其变化幅度非常小。