Indirect transfer to the Earth–Moon L1 libration point

The Earth–Moon L1 libration point is proposed as a human gateway for space transportation system of the future. This paper studies indirect transfer using the perturbed stable manifold and lunar flyby to the Earth–Moon L1 libration point. Although traditional studies indicate that indirect transfer to the Earth–Moon L1 libration point does not save much fuel, this study shows that energy efficient indirect transfer using the perturbed stable manifold and lunar flyby could be constructed in an elegant way. The design process is given to construct indirect transfer to the Earth–Moon L1 libration point. Simulation results show that indirect transfer to the Earth–Moon L1 libration point saves about 420 m/s maneuver velocity compared to direct transfer, although the flight time is about 20 days longer.     

基于虚拟现实技术的川藏铁路地质灾害易发区减灾选线优化:以洛隆车站为例

铁路沿线频发的滑坡泥石流灾害,对山区铁路建设与安全运营造成重大影响。在山区铁路选线过程中,如何科学规划铁路线位和工程方案,真正把铁路地质灾害问题解决在成灾之前,实现科学防灾减灾,已成为国内外学者关注的焦点问题。提出一种基于虚拟现实技术(VR)的铁路地质灾害易发区减灾选线场景仿真系统,利用CAD、Sketch Up等软件制作三维地形环境模型,进行铁路沿线滑坡泥石流灾变演化仿真分析;基于Unity3D平台,应用3Ds Max、Photoshop等软件完成研究区的虚拟铁路场景模型搭建,通过网页版的UI交互设计,实现虚拟铁路场景的三维可视化体验;以新建川藏铁路洛隆车站为例,采用该方法建立了多种线路方案优化。结果表明:所建立的虚拟现实场景系统具有很好的可视性和较为流畅的交互性,可充分展示研究区铁路建设及运营安全的可行性。     

Property insurance against debris-flow disasters based on risk assessment and the principal–agent theory

Dongchuan City is highly threatened by debris-flow disasters originating from Shengou gully, a typical debris-flow gully along Xiaojiang River in Yunnan Province (Kang et al. 2004). Shengou gully is studied, and a hazard assessment with numerical simulation is developed using ArcGIS 9.2 software. Debris-flow numerical simulation is an important method for predicting debris-flow inundation regions, zoning debris-flow risks, and helping in the design of debris-flow control works. Meanwhile, vulnerability measurement is essential for hazard and risk research. Based on the self-organized map neural network method, we combine the six vulnerability indicators to create an integrated debris-flow vulnerability map that depicts the vulnerability levels of Dongchuan City in Shengou Basin. Based on the risk assessment (including hazard assessment and vulnerability assessment), we adopt the principal–agent theory and use the risk degree of debris flows as an important index to build the insurance model and analyze the insurance premium of debris-flow disasters in Dongchuan City. This paper discusses the model and mechanism of property insurance in debris-flow risk regions and aims to provide technical support for insurance companies to participate in disaster prevention and reduction.     

Analysis of influence of natural disaster on the economy and prediction of recovery time based on grey forecasting–difference comparison model: a case study in the upper Min River

Natural Hazards - After the 2008 Wenchuan earthquake, secondary geological disasters occurred frequently and caused huge economic losses in the upper reaches of Min River. In this paper,...     

新疆于田县阿羌火山岩的时代再讨论

阿羌火山岩作为一个独立的地质构造单元在西昆仑的地质演化中扮演着重要的角色。为了调查阿羌火山岩的年龄,在阿羌火山岩的不同部位中采集了5件样品,进行LA-MC-ICP-MS锆石U-Pb定年。其中2件样品没有获得有效年龄,另外3件样品得到4个年龄数据:485Ma、461Ma、432Ma、145Ma,反映该带经历了加里东、华力西、燕山等运动。该结果对重新认识和研究西昆仑的地质演化历史具有重要的地质意义。     

工程VSP模拟和应用问题的研究

本文对在工程地质勘查中常遇到的一些地质模型进行了ＶＳＰ正演模拟,根据正演模拟结果,讨论了在工程ＶＳＰ勘查中应注意的问题,并对工程ＶＳＰ的应用问题进行了讨论。     

Susceptibility mapping of landslides in Beichuan County using cluster and MLC methods

Cluster analysis and maximum likelihood classification (MLC) are exploited to map the post-earthquake landslide susceptibility in Beichuan County that was affected by the Ms 8.0 Wenchuan earthquake. The methodology is applicable even if there is short of training data. Six effective factors are chosen for mapping the susceptibility, including land use, seismic intensity, average annual rainfall, relative relief, slop gradient and lithology. Four clusters are grouped from sampling grid cells by k-means clustering approach. MLC classifies all the cells in the study area into the four clusters according to their statistical characteristics. Four susceptibility classes (extreme low, low, moderate and high) are assigned to these clusters applying expert experience and hazard density. The final map gives a reasonable assessment of post-earthquake landslide susceptibility in Beichuan County. Comparing with the pre-earthquake susceptibility map made in Beichuan County geological disaster survey project, the result t using cluster and MLC classification has a better agreement with the dot density value of post-earthquake landslides in Beichuan County. The susceptibility map can be used to identify safety spots within the high danger area, which are suitable for habitations and facilities. It is also found that more landslides are densely concentrated at the boundary between high and moderate regions, and between high and extreme low regions.     

农业综合生产潜力指标体系及其模型改进

在系统分析自然生产潜力经典研究成果的基础上,进一步考量社会经济因素的影响,根据土、肥、水、种、密、保、管、工8个影响作物产量形成的主要社会经济因素构建社会经济生产潜力系统,形成了较为完善的农业综合生产潜力指标体系;并引入社会经济修正函数对现有的农业自然生产潜力模型进行完善,构建农业综合生产潜力模型。农业综合生产潜力指标体系及其模型,为定量评估农业资源利用程度提供了一种有效手段。     

酒西坳陷石北次凹油气生成、运移成藏及勘探方向

酒泉盆地酒西凹陷石北次凹油气勘探历经70余年,仅在古近系发现了白杨河和单北两个小型油田。虽然许多探井在白垩系中也见到良好油气显示,但仅少数探井获得了低产油流,油气勘探始终未获得大突破。该凹陷究竟有没有勘探潜力以及油气勘探方向始终不清楚。通过对该凹陷大量烃源岩样品地球化学分析研究发现,该凹陷发育下白垩统中沟组、下沟组和赤金堡组三套潜在烃源岩。中沟组烃源岩有机质丰度较低、以Ⅲ型有机质为主,处于未成熟阶段,没有生油能力;下沟组和赤金堡组烃源岩有机质丰度高、以II有机质为主,属于优质烃源岩,其中下沟组烃源岩处于未成熟—低成熟阶段,仅具有生成少量低成熟原油的可能性,赤金堡组烃源岩处于低成熟—成熟阶段,具有生成低成熟和成熟石油的能力。石北次凹烃源岩主要生油期为新近纪末期至第四纪早期,目前生烃作用已基本停止。石北次凹已经发现了三种不同类型原油,第一类原油为低成熟原油,分布于浅层古近系,来源于石北次凹低成熟的赤金堡组上段烃源岩;第二类原油为中等成熟原油,分布于西部斜坡浅层古近系,来源于青南次凹下沟组中段烃源岩;第三类原油为成熟原油,分布于凹陷深层赤金堡组砂岩储层,来源于石北次凹成熟的赤金堡组中下段烃源岩。白杨河、单北和单东油田原油属于第二类原油,为长距离运移成藏,鸭儿峡至石北次凹西部斜坡地区为该类原油有利的勘探区域,古近系则为主要勘探目标层系。白南3井、白南6井赤金堡组原油属于第三类原油,为近距离运移自生自储型油藏,石北次凹中北部深层赤金堡组为该类原油最有利的勘探目标层系,包括常规油藏和非常规致密油藏。     

都市区调查深埋活断层的地震方法技术

地震方法是调查深埋断层的主要手段,在闹市区,表层地震地质条件的复杂性和人文活动的频繁性,使得地震方法的应用受到了很大限制。在适当的工作时间,采用相关和水平叠加技术、使用较高频率的检波器和滤波器,并采取一些其它的数据采集技术和相应的数据处理技术,有利于压制强背景干扰,提高地震记录的信噪比和分辨率,获取高质量的地震时间剖面。