花岗岩地区病险水库工程地质问题及处理措施

花岗岩地区病险水库的险情主要为坝基渗漏,高水位运行期坝脚易发生管涌而限制水库效益的发挥。以某病险水库为例,分析总结了花岗岩地区以风化料作为坝体填料的主要地质问题;对坝基花岗岩深厚的风化壳、差异风化以及河床冲洪积砂砾卵石层等主要工程地质问题进行了评价;针对主坝、副坝及溢洪道的防渗加固,提出了相应的工程措施。对其他典型花岗岩地区的病险水库工程勘察有一定参考价值。     

Analysis of microwave brightness temperature of lunar surface and inversion of regolith layer thickness:Primary results of Chang-E 1 multi-channel radiometer observation

In China’s first lunar exploration project, Chang-E 1 (CE-1), a multi-channel microwave radiometer was aboard the satellite, with the purpose of measuring microwave brightness temperature from lunar surface and surveying the global distribution of lunar regolith layer thickness. In this paper, the primary 621 tracks of swath data measured by Chang-E 1 microwave radiometer from November 2007 to February 2008 are collected and analyzed. Using nearest neighbor interpolation based on the sun incidence angle in ...     

月球漫游车关键技术初探

参考国外月球探测的现状,对月球车所涉及的关键技术问题进行了深入地分析与探 讨,提出了开发我国月球漫游车系统的具体实施方案．并针对月面的复杂环境,提出了建立 一套智能传感系统的思想,从而为实现漫游车在月面复杂、未知的环境中的自主导航与控制 提供了理论依据．     

HIT-1型月球车的运动学分析

为解决轮式移动机器人在崎岖地形中的运动问题，提出了基于摇杆-转向架的带有弹簧和移动滑块的月球车运动学分析方法，在此基础上详细分析了HIT-l型月球车的3D运动机制，推导了月球车的正向运动和反向运动求解．通过使用弹簧和关节滑块改变车体的质心分布，可加强车体运动重构性，提高车体的牵引力，有效地规划和控制月球车的动作．     

有限推力登月飞行器燃料消耗研究

首先介绍了使用基于双二体问题的圆锥曲线拼合法和齐奥尔科夫斯基公式进行登月飞行器燃料消耗量的计算方法;接着导出了地月固联三体坐标系中最优轨道情况下登月飞行器燃料消耗量的计算方法;最后给出了在一定推力范围内不同比冲常规发动机分别使用上述第1种方法得到的燃料消耗和使用上述第2种方法得到的发动机工作时间和燃料消耗的仿真结果。结果表明两种方法得到的结论吻合得很好。     

Bearing capacity of surface circular footings on granular material under low gravity fields

Low gravity fields have been simulated through magnetic acceleration to conduct experimental study on bearing capacity of circular footings on a type of crushable planetary regolith simulant,which has comparable density and particle size distribution of lunar soil.The load-settlement responses of surface spread footings are obtained by investigating the relative density,footing size and gravity effects.Applying the hyperbolic asymptote method,normalised foundation stiffness and ultimate bearing capacity are obtained by curve fitting and predicted by power functions using multivariate nonlinear regression.The results show that the nonlinear gravity effect is not negligible,related to stress condition,soil dilatancy and mobilised friction angle.A cone penetration test(CPT)-based method for prediction of bearing capacity is proposed with correlations between ultimate bearing capacity of footings and shallow penetration stiffness of CPTs,avoiding the uncertainties of soil property estimations.Analyses of allowable bearing capacity and footing influence zone in consideration of footing size and gravity effects could therefore improve the design of shallow foundations on the Moon and Mars,and provide new understandings and potential implications to the bearing capacity of shallow foundations on crushable granular material in both terrestrial and extraterrestrial geotechnical engineering.     

向月飞行轨道误差分析

根据月球探测器向月飞行轨道动力学方程式得到了飞行轨道误差的迭代方程,采用协方差分析方法对轨道初始误差误差源造成的轨道误差进行了分析,结合具体算例,给出了探测器初始轨道位置和速度误差引起的向月飞行轨道误差的时间历程和轨道终点误差。计算结果表明,若发射环月卫星,必须进行多次中途轨道修正。     

基于最小二乘法的月球探测器自主导航

对于地月转移轨道的月球探测器,其受力复杂,轨道动力学方程难以精确建立,因此难以应用已有的基于轨道动力学方程的滤波方法对其进行自主导航.文中提出了以太阳和恒星的天文信息为观测量,采用迭代最小二乘法进行纯几何解析定位来实现月球探测器自主导航的方法.最后还对定位结果的优化的进行了研究.通过数学仿真分析了敏感器精度、观测星个数等因素对定位精度的影响,结果表明这种方法简单可靠,可以作为深空探测自主导航的滤波方案的初值.     

A neutronics analysis of long-life, sectored compact reactor concepts for lunar surface power

Neutronics analysis is performed of low temperature (≤900 K) Sectored Compact Reactor (SCoRe-N_x) concepts for operational lives >20 years. They are cooled with circulating liquid Nak-78. The reactor vessel and the UN fuel pins cladding are made of stainless steel. The power systems with the SCoRe-N_x concepts have no moving parts and employ SiGe thermoelectric elements for converting the reactor’s thermal power to electricity at a load voltage >300 VDC. Separate SiGe elements power the electromagnetic pumps that circulate the liquid NaK-78 in the reactor and 6 pairs of primary and secondary loops. Analysis confirmed that the submerged bare reactors in wet sand and flooded with seawater, in the unlikely event of a postulated launch abort accident, are sufficiently subcritical. Results show that the SCoRe-N₅-S concept is capable of operating for 62 full power years at 200 kW_th, while requiring 75% of the control drums to shutdown the reactor at BOL. With only 50% of the control drums required at BOL to shutdown the reactor, its operational life decreases to 39 full power years.     

A general framework for three-dimensional surface reconstruction by self-consistent fusion of shading and shadow features

In this paper a novel framework for three-dimensional surface reconstruction by self-consistent fusion of shading and shadow features is presented. Based on the analysis of at least two pixel-synchronous images of the scene under different illumination conditions, this framework combines a shape from shading approach for estimating surface gradients and altitude variations on small scales with a shadow analysis method that allows for the determination of the large-scale properties of the surface. As a first step, the result of shadow analysis is used for selecting a consistent solution of the shape from shading reconstruction algorithm. As a second step, an additional error term derived from the fine-structure of the shadow is incorporated into the reconstruction algorithm. This approach is extended to the analysis of two or more shadows under different illumination conditions leading to an appropriate initialization of the shape from shading algorithm. The framework is applied to the astrogeological task of three-dimensional reconstruction of regions on the lunar surface using ground-based CCD images and to the machine vision task of industrial quality inspection.