Dynamics of the CH4+ O(~3 P) → CH_3(ν= 0) + OH(■= 0) reaction

The dynamics of the ground-state reaction of CH_4+ O(~3P) → CH_3(ν = 0) + OH( ν= 0) have attracted a great deal of attention both theoretically and experimentally. This rapid communication represents extensive quasi-classical trajectory calculations of the vibrational distributions on a unique full-dimensional ab initio potential energy surface for the title reaction, at the collision energy of relevance to previous crossed molecular beam experiments. The surface is constructed using the all electrons coupled-cluster singles and doubles approach plus quasi-perturbative triple excitations with optimized basis sets. A modified Shepard interpolation method is also employed for the construction. Good agreement between our calculations and the available experimental results has been achieved, opening the door for accurate dynamics on this surface.     

星光观测蒙气差补偿技术

为了消除大气内观星时蒙的影响,提高载体定姿精度,提出了一种蒙气差补偿算法。首先给出了补偿过程涉及的姿态转移矩阵,并完成了相关矢量坐标映射变换;接着在星敏感器坐标系内,用两矢量内积法求得视天顶距;最后利用几何公式列出了以真星光矢量投影点估计位置为未知量的方程组,作为星敏感器任意姿态下蒙气差补偿算法模型。在没有任何误差的条件下对模型有效性进行了仿真,10-6 pixel量级的位置估计精度表明了算法的有效性。加入不同量级的陀螺漂移误差进行了仿真,给定的漂移误差对于蒙气差补偿模型的估计精度影响甚微,仿真结果表明在捷联载体存在一定姿态误差的前提下,蒙气差补偿模型也是适用的,补偿后的星像坐标用以实现星光姿态确定,并进一步对陀螺漂移完成补偿。     

静态像点高斯灰度扩散模型参数估计方法

为了实现星敏感器高斯灰度扩散模型的参数估计,设计了平行光管成像标定实验及相关算法。基于高斯规律建立并求解了以高斯扩散半径和像点质心坐标偏差为变量的方程组,进一步求得灰度能量系数;在3个不同平行光源方位拍摄图像,利用图像灰度数据计算模型参数的系列测量值,分别取均值作为其估计值;建立实验验证方法,将3个估计参数代入模型模拟静态星像点,将模拟图像与存在噪声的实拍图像做相似度比较,3pixel×3pixel窗口内相似度高于0.97,5pixel×5pixel窗口内高于0.98,7pixel×7pixel窗口内高于0.98。结果表明,方程组求解得到的高斯扩散半径、像点质心偏差的值可信,推导公式正确。