GPS卫星轨道精度对定位结果的影响

卫星轨道误差是影响定位精度的重要误差源,在轨道精度、表示方式和实时性等方面对广播星历、超快速星历、快速星历和精密星历进行了比较分析,得出广播星历与精密星历所提供的卫星轨道相差较大,超快速星历居中,快速星历轨道与精密轨道接近,在测量设备的高精度比对鉴定中,满足不同试验需求对卫星星历的选择提供了依据。     

安徽沿江地区中生代岩浆岩的基本特点

安徽沿江地区位于长江中下游岩浆带中段,中生代岩浆活动强烈,类型复杂,特点突出。它具有夹心饼干式分带现象。中间为富碱的高钾钙碱性岩系和橄榄安粗岩系;两侧为钙碱性岩系。中间的岩浆岩具有高钾富碱、高Ｓｒ,低Ｍｇ、Ｃｒ、Ｎｉ,εＮｄ变化大但Ｉｓｒ变化小且较低以及岩浆演化的多样性为特点。     

Predicting landslide sliding distance based on energy dissipation and mass point kinematics

Natural Hazards - Based on classical mechanics and the law of energy conservation, we present a model for predicting landslide sliding distance. We conceptualize landslide movement as the movement...     

滑坡灾害环境与山区建设的和谐

滑坡是浙江省沿海及丘陵山区频发的地质灾害之一,常堵塞交通、农田毁损、民房倒塌、使山区人民生活环境严重恶化。分析滑坡灾害机理,提早预警预报,是合理规划山区民居建设、治理地质灾害、建立民居与生态环境合谐的的关系,是各级政府、地质工程界、建设部门和环境监理部门的重要社会责任和理论研究范围。     

土层地震反应传递函数的模拟

探讨了用单一土层模型替换复杂场地求解土层场地传递函数的方法,并用ＳＭＡＲＴ－１台阵地震记录对这一方法的可行性进行了研究和讨论,结果表明,只要选取适当的地震波入射角Ψ和土介质的滞回阻尼比ｄ,简化模型的传递函数与实际传递函数能符合得较好,这一方法可用来近似估计缺少详细土质勘测资料地区的土层地震反应的传递函数。     

Heat flow pattern, base of methane hydrates stability zones and BSRs in Shenhu Area, northern South China Sea

Using the collected 433 heat flow values, we estimated the bases of methane hydrate stability zone (BHSZ), in northern South China Sea (NSCS). Through comparing BHSZs with the depths of bottom simulating reflectors (BSRs), in Shenhu Area (SA), we found that there are big differences between them. In the north of SA, where the water depth is shallow, many slumps developed and the sedimentation rate is high, it appears great negative difference (as large as -192%). However, to the southeast of SA, where the water depth is deeper, sedimentation rate is relatively low and uplift basement topography exists, it changes to positive difference (as large as +45%). The differences change so great, which haven’t been observed in other places of the world. After considering the errors from the process of heat flow measurement, the BSR depth, the relationship of thermal conductivity with the sediments depth, and the fluid flow activities, we conclude that the difference should be not caused by these errors. Such big disagreement may be due to the misunderstanding of BSR. The deviant “BSRs” could represent the paleo-BSRs or just gas-bearing sediment layers, such as unconformities or the specific strata where have different permeability, which are not hydraterelated BSRs.     

沟槽内海底管道的水动力特性研究

基于水力模型实验，引入相对沟形系数αｒ，获得了以αｒ为表征的相对水动力系数与ＫＣ数的关系；对于浅沟而言，这种关系较有规律性。根据所设计沟形的αｒ值和所选定的ＫＣ值，应用本文结果，可以方便地判断其力折减程度和掩护效果     

结合速度障碍法的无人艇编队控制策略研究

在实际的工程运用中,领航者–跟随者算法无法解决无人艇在编队形成过程中的相互碰撞问题,往往需要提前确定编队初始状态,避免编队无人艇之间的相互碰撞。针对该缺陷,将速度障碍法引入领航者–跟随者算法,并将威胁评价引入速度障碍法中,以解决无人艇在编队过程中的相互碰撞问题。建立了无人艇的运动仿真平台,并对提出的无人艇编队控制策略进行了仿真试验。试验表明：该算法提高了编队控制的稳定性,降低了编队形成过程中的碰撞风险。     

A Lagrangian study of the near-surface intrusion of Pacific water into the South China Sea

Satellite-tracked Lagrangian drifters are used to investigate the transport pathways of near-surface water around the Luzon Strait. Particular attention is paid to the intrusion of Pacific water into the South China Sea(SCS).Results from drifter observations suggest that except for the Kuroshio water, other Pacific water that carried by zonal jets, Ekman currents or eddies, can also intrude into the SCS. Motivated by this origin problem of the intrusion water, numerous simulated trajectories are constructed by altimeter-based velocities. Quantitative estimates from simulated trajectories suggest that the contribution of other Pacific water to the total intrusion flux in the Luzon Strait is approximately 13% on average, much smaller than that of Kuroshio water. Even so, over multiple years and many individual intrusion events, the contribution from other Pacific water is quite considerable. The interannual signal in the intrusion flux of these Pacific water might be closely related to variations in a wintertime westward current and eddy activities east of the Luzon Strait. We also found that Ekman drift could significantly contribute to the intrusion of Pacific water and could affect the spreading of intrusion water in the SCS. A case study of an eddy-related intrusion is presented to show the detailed processes of the intrusion of Pacific water and the eddy-Kuroshio interaction.