Pore pressure profiles in fractured and compliant rocks1

Fluid permeability in fractured rocks is sensitive to pore-pressure changes. This dependence can have large effects on the flow of fluids through rocks. We define the permeability compliance γ= 1/k(k/δp_p)_pc, which is the sensitivity of the permeability k to the pore pressure p_p at a constant confining pressure p_c, and solve the specific problems of constant pressure at the boundary of a half-space, a cylindrical cavity and a spherical cavity. The results show that when the magnitude of permeability compliance is large relative to other compliances, diffusion is masked by a piston-like pressure profile. We expect this phenomenon to occur in highly fractured and compliant rock systems where γ may be large. The pressure profile moves rapidly when fluids are pumped into the rock and very slowly when fluids are pumped out. Consequently, fluid pressure, its history and distribution around injection and production wells may be significantly different from pressures predicted by the linear diffusion equation. The propagation speed of the pressure profile, marked by the point where δp_p/δx is a maximum, decreases with time approximately as and the amplitude of the profile also dissipates with time (or distance). The effect of permeability compliance can be important for fluid injection into and withdrawal from reservoirs. For example, excessive drawdown could cause near-wellbore flow suffocation. Also, estimates of the storage capacity of reservoirs may be greatly modified when γ is large. The large near-wellbore pressure gradients caused during withdrawal by large γ can cause sanding and wellbore collapse due to excessive production rates.     

Die Rheingrabenrandverwerfung im Wattkopftunnel bei Ettlingen (Nordschwarzwald)

The Wattkopftunnel, near Ettlingen (Nordschwarzwald), drives through the eastern margin of the Rheingraben. The tunnel passes cenozoic and mesozoic sediments. Early quarternary and tertiary beds are situated west of the main thrust of the Rheingraben. Fossil record indicates upper Oligocene age (Chatt) for parts of the tertiary sediments. At the eastern border of the Rheingraben, wedges of jurassic and middle triassic series are squeezed. East of the Rheingraben the tunnel drives in the lower triassic Bausandstein. The eastern margin of the Rheingraben was investigated in detail during tunneling. Faults of the Rheingraben margin are distributed in an 130 meter wide fault zone in the tunnel. Total stratigraphic separation by the normal faults reaches more than 2 000 meters. The cenozoic sequence suffered synsedimentary to early diagenetic deformation, while the mesozoic series are characterized by ruptural deformation. The fault- and joint system is directed in the rheinische Richtung (SSW-NNE). East of the Rheingraben a second direction occur, running parallel to the lower Albtal (W-E).

     

新疆地区夏季平流层低层风场特征分析及数值模拟

利用2017年6—8月的FNL再分析资料分析了新疆地区夏季平流层低层风场的时空演变特征，开展了平流层低层风场的高分辨率数值模拟和检验。结果表明：新疆地区夏季平流层纬向风随时间的变化存在经向差异，同时准零风层开始和结束的时间也存在经向差异，准零风层开始时间南部地区早于北部地区，而准零风层结束时间则相反。整个夏季新疆地区上空的准零风层处于70～40 hPa之间，其高度随时间呈先降低而后升高的变化趋势。准零风层数值模拟结果表明，模拟的准零风层参数与探空资料分析结果相比二者存在一致的变化趋势，准零风层起始高度的平均绝对误差为467 m，该高度对应的风速均方根误差为1.75 m/s。     

OBE理念下GIS空间分析课程思政教学设计与实践

以成果导向教育(Outcome Based Education,OBE)和课程思政理念为指导进行课程设计与实践,是地理信息科学专业应用型人才培养的发展趋势.围绕专业人才培养目标和课程教学目标,以反向设计为原则,结合专业毕业要求,确定课程学习成果,然后以成果为导向,设计实施教学改革,将思政元素有机融入专业教学中,培养学生综合素养.地理信息系统(Geographic Information System,GIS)方向的课程《GIS空间分析》是地理信息科学专业核心课程,探索和实施成果导向下的课程思政教学目标的达成,围绕教学目标进行有效的教学设计,结合课程内容从理论知识和实践操作两个层面进行课程思政教学融入设计,提出课程思政融入专业课教学的典型案例和实施路径,包括制定课程目标、确定学习成果、探索和实施新型教学方式、优化课程考核和评价方式等方面.     

碳中和目标下关键矿产在清洁能源转型中的作用、供需分析及其建议

在"碳中和"目标的驱动下，全球能源系统向清洁化、低碳化甚至无碳化发展已是大势所趋。针对向清洁能源转型的需求，采用了统计对比、分类汇总、综合分析等方法，分析研究了关键矿产在电池、电网、低碳发电和氢能等行业中的作用和需求。结合当前关键矿产产量的地理集中度高、项目开发周期长、资源质量下降等矿产供应和投资计划不能满足清洁能源转型的需求等问题，提出确保关键矿产多样性供应，推动价值链各环节的技术创新，扩大回收利用，增强供应链弹性和市场透明度，将更高的环境、社会和治理标准纳入主流程及加强生产者和消费者之间的国际合作等建议。     

Universal birefringent filter with a new double passband mode

This article describes the universal birefringent filter (UBF) which will be mounted at Taiwan. The UBF permits observations of solar images, vector magnetic fields and/or line-of-sight velocity fields in any Fraunhofer line in the wavelength region from 4000 to 7000 with half width from 0.05 to 0.14 . We have tested it at ten Fraunhofer lines under a spectral telescope in Huairou Station of Beijing Astronomical Observatory and obtained the passband profiles. The principles of magnetic field and velocity field measurement with the UBF are also described.     

青藏高原腹地湖泊沉积对第四纪晚期古季风变化的响应

通过对青藏高原腹地的综合科学考察和对中心钻孔岩芯剖面的最新研究,用层序地层学与年代地层学和气候地层学相结合的方法,分辨出可可西里地区湖泊沉积记录(孔深7.25 m)的第四纪晚期距今3万余年以来的古气候变化,沉积物磁化率等因子综合表征的高原古季风变化是波动发展的,发生在仙女木期地质环境事件中的季风活动具有强烈暴发的特点,是高原季风发展中的突变事件,而且地表热点效应对其起到了激发作用。综合分析的研究成果表明,它的变化频谱与激变因子及其运行机制是伴随着青藏高原地质效应的演变而发展的,为研究第四纪冰消期以来的气候变化提供了新的信息。     

预应力锚索在公路高陡边坡加固整治工程中的应用

预应力锚索锚固技术以其结构合理、工艺灵巧、适应性广、施工速度快、造价低等优势，目前已广泛应用于各工程领域。在桂（林）—柳（州）高速公路高边坡加固工程中采用了该项技术，经过近1年的运转表明，效果良好。对该项工程作了详细讨论，介绍了边坡的地质条件、稳定性分析和设计参数的选取，总结了施工中锚索的造孔、下索、注浆、张拉锁定等设计及施工要点。     

益母草水苏碱对钉螺生理生化的影响

本实验研究了益母草水苏碱对钉螺糖原和总蛋白的生理生化影响:大于0.80g/L益母草水苏碱能够显著降低钉螺体内的糖原含量,减少幅度从11.68%到76.16%;益母草水苏碱也能够在一定程度上降低钉螺体内的蛋白质含量(从5.66%到13.69%),但减少量不及糖原显著;灭螺植物对钉螺的致死作用可能更多与钉螺组织细胞中的能量代谢有关。     

北京地区湿地高等植物区系分析

根据工作需要,在北京4个水系的主要河流的平原地段和山区的上、中游地段,选取不同生境的典型样地,以及城区的人工湖泊共设立了35个采集点,采用样方法和样带法相结合,共调查样方355个,采集样本4 152个。在该调查资料的基础上,运用区系学原理对北京地区湿地高等植物区系的种类组成、地理成分(科、属、种3个层次)等进行了系统的分析。结果表明,北京地区湿地高等植物共有108科311属552种(含山区湿地),占北京植物总数的近1/3。其中苔藓植物(B ryohyto)有9科15属18种;蕨类植物(Pteridophgta)5科5属8种;裸子植物(Gymnosperm ae)3科5属6种;被子植物(Angiosperm ae)91科286属520种。种子植物中含20种以上的有5科,共210种;含5种以上的属有14个属,共114种。北京地区湿地植物的分布(即地理成分)较复杂。北京湿地种子植物属的分布区类型有15个类型,9个变型,温带地区类型占主导,温带成分较丰富(属数、种类、比例均占首位)。本区植物区系的主要特征为:①草本植物发达;②温带成分占优势地位;③区系起源古老;④特有属、种匮乏;⑤分布区类型具多样性。