山东地区水化学短临跟踪标志体系的研究

在系统整理山东地区水化学观测资料的基础上,对山东菏泽５．９级地震、苍山５．２级地震及大同６．１级地震和南黄海５．３级地震前的地震异常特征进行了分析和总结。认为水化学多组分的同步异常变化,同震源应力场孕育过程,多组分的同步异常变化,具有统一的物理力学机制,是震前源兆异常的重要标志,这些异常基本同步出现,相互印证,增强了异常的可信度,为短临异常的判定提供了较为充分的依据。某一井孔水化学多发出现同步异常     

1983年山东菏泽5.9级地震地下流体异常的检验性预测

本文对１９８３年山东菏５．９级地震震中周围２００ｋｍ范围内８口井１７个测地下流体观测资料,采用地下流体群体异常演化层次跟踪法,对菏治５．９级地震进行了中期,短期和短临三个时间尺度的震情预测,     

透射式微焦点X射线源钨-金刚石靶材的制备及其性能研究

本文采用磁控溅射镀膜技术制备了钨-金刚石透射靶材,借助电子扫描电镜对靶材的钨薄膜进行微观形貌分析。同时借助YXLON光机,研究自制靶材在X射线出射率及其产生X射线所需消耗功率和寿命等性能,并与YXLON原带靶材进行性能比较。研究表明,采用磁控溅射制备的钨薄膜与YXLON靶材上的钨薄膜具有相似的表面形貌;在YXLON光机相同工作条件下,自制靶材的X射线出射率略高于YXLON原带靶材的X射线出射率的1%,二者辐射X射线所需的功率相差无几,自制靶材的寿命要长于YXLON靶材的。这表明自制钨-金刚石靶材能够满足微焦点射线源所需的高质量靶材的应用要求。      

Application Study on Correction Method for Lag of Water Level Response to Earth Tide and Atmospheric Pressure

INTRODUCTIONBased onthe results gathered after manyyears of seismic groundwater observation,itisfoundthatthe water level in deep wells responds to the earth’s tide and atmospheric pressure and changesaccordingly,not onlyin amplitude ,but also in the phase lag by different degrees .Some phase lagslast onlyfor several minutes ,while some last aslong as more than one hour (Zhang Zhaodong,1988 ;Wang Chengmin,1990) .The result of this theoretical research shows that the phase lag response to…     

土−水特征曲线测量过程中孔隙分布的演化规律探讨

测量了在宽广吸力范围内原状样和压实样的脱湿持水曲线,对比分析了单双峰结构持水性能的差异;并利用压汞试验测试两种土样在脱湿过程的孔隙分布,分析了两者的差异并探讨了脱湿过程孔隙的演化规律;在考虑收缩变形的基础上,基于孔隙分布曲线确定了土?水特征曲线的基本参数。试验结果表明：原状样在宽广吸力范围内基本上呈单峰孔隙结构;饱和压实样具有单峰孔隙结构,随着吸力的增加,双峰结构越来越明显,当吸力达到很大时,演化成完全双峰孔隙结构。原状样的持水曲线为经典的S形,而压实样的持水曲线在过渡段出现了水平台阶状;低吸力段,压实样的持水曲线低于原状样,而高吸力段,两者的持水曲线基本重合。基于孔隙分布曲线确定了控制持水曲线进气值和残余值的孔径,并计算出对应的吸力值,其值更符合实际物理意义。     

Flood risk assessment in Quzhou City (China) using a coupled hydrodynamic model and fuzzy comprehensive evaluation (FCE)

Natural Hazards - To evaluate urban flood risk while considering spatial and temporal characteristics, this paper establishes an assessment method based on a coupled hydrodynamic model and a fuzzy...     

Kinematic precise point positioning at remote marine platforms

Precise kinematic differential positioning using the global positioning system (GPS) at a marine platform usually requires a relatively short distance (e.g. <500 km) to a land-based reference station. As an alternative, precise point positioning (PPP) is normally considered free from this limiting requirement. However, due to the prerequisite of network-based satellite products, PPP at a remote marine platform may still be affected by its distance to the reference network. Hence, this paper investigates this scenario by configuring rings of reference stations with different radii centered on a to-be-positioned marine platform. Particularly, we applied ambiguity resolution at a single station to PPP by estimating uncalibrated phase delays (UPDs). We used three rings of reference stations centered on a vessel, with radii of roughly 900, 2,000 and 3,600 km, to determine satellite clocks and UPDs independently. For comparison, we also performed differential positioning based on a single reference station with baseline lengths of about 400, 1,700 and 2,800 km. We demonstrate that, despite the increasing ring-network radius to a few 1,000 km, the overall change in accuracy of the satellite clocks that are used at the vessel is smaller than 0.02 ns, and the RMS values of differences between the three sets of narrow-lane UPD estimates are around 0.05 cycles only. Moreover, the kinematic positioning accuracy of PPP is affected by the increasing ring-network radius, but can still achieve several centimeters after ambiguity resolution when the vessel is over a few 1,000 km away from the ring network, showing better performance than that of differential positioning. Therefore, we propose that ambiguity-fixed PPP can be used at remote marine platforms that support precise oceanographic and geophysical applications in open oceans.     

Field study of monotonic and cyclic lateral behaviour of piles in soft soils improved with and without vacuum preloading

Acta Geotechnica - Project Oufei is the largest individual reclamation project in Wenzhou city, China, and the main infrastructure consists of seawalls, sluices and separation dikes. These...     

Debris flow dam formation in Southeast Tibet

1 Introduction Debris flows in Southeast Tibet can carry a great deal of sediment into streams in a special way. They block mainstreams and form dams.This type of dam,not only dominates the interaction between water and sediment and changes in the riverbed, but also exerts a great influence on the ability of transportation of the river. When a debris-flow dam forms, the water level behind the dam will increase, and villages, fields and roads will beflooded.When the dam breakes,the resulting …     

Assessing the relative contributions of the flood tide and the ebb tide to tidal channel network dynamics

Flood and ebb currents provide different contributions to the initiation and evolution of tidal channel networks, generating diverse network structures and channel cross-sections. In order to separate the effects of these contributions, a physical model of a sloping tidal-flat basin was set up in the laboratory. Depending on the degree of tidal asymmetry imposed offshore, either flood or ebb currents can be enhanced. The experimental results show that the ebb current has a higher capability to initiate and shape tidal networks than the flood current. Headward erosion is mainly induced by the ebb flow. The slightly inclined flat surface tends to reduce the energy of the flood current and to enhance the ebb current, thus prolonging the duration of morphodynamic activity as well as sediment motion. Overall, flood-dominated tides favour the formation of small-scale channel branches in the upper basin zone, while long lasting ebb-dominated tides result in more complex, wider and deeper tidal networks. © 2019 John Wiley & Sons, Ltd.