热化学非平衡流动红外辐射计算分析

首先通过求解热化学非平衡N-S方程的数值模拟方法,获得高焓风洞钝锥体模型的绕流及近尾的高温流场参数.然后从辐射传输方程出发,采用带辐射模型,并利用所获得的流场参数,计算分析了高温流场在λ=3μm-6μm红外波段的辐射,计算和测量结果具有较好的一致性.该项研究为今后进一步研究高温非平衡气体辐射特性奠定了基础.     

波瓣喷管/气膜冷却混合管气动和红外辐射特性实验

 针对某型后向进气、前向排气的涡轴发动机用红外抑制器,提出了波瓣喷管和气膜冷却混合管组合的红外抑制概念,旨在进一步降低混合管壁面红外辐射强度。用实验的方法,对气膜混合管内流特性、红外辐射特性进行了研究。研究结果表明：混合管壁面的3个引射入口的静压都低于外界大气压力,从而自然形成引射驱动动力;引射流量比与主、次流温度比有关,通过实验得到的温度修正指数可以将冷态实验结果外推到热态情况;与一般混合管相比,整体引射流量提高30％,在3~5 μm波段内,红外辐射强度降低了12%~27%,在8~14 μm波段内,红外辐射强度降低了12%~28%,其总压损失仅仅提高了1%。     

卫星舱内两类剂量计测量结果的比较

本文利用1994年和1996年两次返回式卫星的搭载条件对舱内辐射剂量进行了对比测量．通过对比测量,研究不同掺杂、不同厚度LiF剂量计测量空间辐射剂量的特点;研究GM计数管计数和LiF剂量间的转换系数以及转换系数随屏蔽状况的变化;由剂量和GM计数研究粒子平均碰撞阻止本领的估计方法．结果表明,不同掺杂、不同厚度的LiF剂量计测量结果间无显著差异,而转换系数几乎不受舱内位置和屏蔽状态的影响．不同厚度LiF剂量计,不同屏蔽状态的GM计数管计数和剂量—计数转换系数的比较研究以及对粒子平均碰撞阻止本领的估计表明,舱内辐射剂量起决定作用的是高能粒子成分,其平均碰撞阻止本领估计约为5MeV／cm．     

密闭舱内氧传感器自动标定方法研究

鉴于氧浓度传感器、氧化锆传感器本身的特性,处于寿命末期的传感器在测量时,会出现精度误差及漂移特性。为减小传感器漂移影响,基于多传感器数据融合技术,选择稳定性及一致性较好的传感器测量值作为自动标定基准值,并在这一基础上,改单点k值标定方法为多点k值标定方法。验证结果显示:当电压值漂移量达到0.1 V时,常规标定方法氧分压漂移量将超过2 kPa,漂移量不超过0.5 kPa。因此,该标定方法增加了氧传感器漂移的适应范围,降低了测量误差,减少了标定的频次。     

Space-radiation-induced photon luminescence of the Moon

We report on the results of a continuing study of the photon luminescence of the Moon induced by Galactic Cosmic Rays (GCRs) and space radiation from the Sun, using the Monte Carlo program FLUKA. Understanding the space radiation environment is critical to future exploration of the Moon, and this includes photons. The model of the lunar surface is taken to be the chemical composition of soils found at various landing sites during the Apollo and Luna programs, averaged over all such sites to define a generic regolith for the present analysis. This surface model then becomes the target that is bombarded by Galactic Cosmic Rays (GCRs) and Solar Energetic Particles (SEPs) or Solar Particle Events (SPEs) above 1 keV in FLUKA to determine the photon fluence albedo produced by the Moon’s surface when there is no sunlight and Earthshine. The result is to be distinguished from the gamma-ray spectrum produced by the radioactive decay of radiogenic constituents lying in the surface and interior of the Moon. From the photon fluence we derive the spectrum which can be utilized to examine existing lunar spectral data and to aid future orbiting instrumentation in the measurement of various components of the space-radiation-induced photon luminescence present on the Moon.     

基于飞行数据反演解算的 SINS空中标定技

针对机载 SINS定期拆卸并进行实验室标定存在的维护效率低、标定周期不合理的问题,提出一种基于 GPS/SINS组合导航仿真飞行数据反演解算的免拆卸空中标定方法。在对飞行数据拟合插值的基础上,利用飞行数据序列和 SINS反演算法解算出惯性器件的输出增量,以引入误差后的惯性器件输出值作为 SINS的输入进行纯惯导解算,并以 SINS和 GPS输出的速度误差作为系统级标定 Kalman滤波器的观测量,对惯性器件误差项进行滤波估计。仿真结果表明,这种标定方法可较好地估计出 SINS中的误差项,实现了 SINS的免拆卸标定,降低了对 SINS定期标定的要求。     

Artificial equilibrium points and bi-impulsive maneuvers to observe 243 Ida

In the restricted three-body problem, the traditional Lagrange points L₁ and L₂ are the only equilibrium points near the asteroid 243 Ida. The thrust generated by a solar sail over a spacecraft enables the existence of new artificial equilibrium points, which depend on the position of the spacecraft with respect to the asteroid and the attitude of the solar sail. Such equilibrium points generate new spots to observe the body from above or below the plane of motion. Such points are very good observational locations due to their stationary condition. This work provides a preliminary analysis to observe Ida through the use of artificial equilibrium points as spots combined with transfer maneuvers between them. Such combination can be used to observe the asteroid from more different points of view in comparison to fixed ones. The analyses are made for a spacecraft equipped with a solar sail and capable of performing bi-impulsive maneuvers. The solar radiation pressure is used both to maintain the equilibrium condition and to reduce the costs of the transfers and/or to create transfers with longer duration. This is a new aspect of the present research, because it combines the continuous thrust with initial and final small impulses, which are feasible for most of the spacecraft, because the magnitudes of the impulses are very low. These combined maneuvers may reduce the transfer times of the maneuvers in most of the cases, compared with the maneuvers based only on continuous thrust. Several options involved in these transfers are shown, like to minimize the fuel spent ($\mathrm{\Delta }\mathit{v}$) as a function of the transfer time or to extend the duration of the travel between the points. Extended transfer times can be useful when observations are required during the transfers.     

姿控发动机推力测量系统的动态建模与补偿

在姿控发动机的瞬态推力测量中,推力测量系统的动态特性是影响推力准确测量的一个至关重要的因素。根据姿控发动机推力测量的特点,针对某型号姿控发动机设计了专用的试车台架,采用了动态标定、动态补偿和计算机仿真有机结合的方法,对推力测量系统动态特性的改善进行了研究。仿真结果表明,此方法在改善推力测量系统动态性能方面是行之有效的,可将其进一步推广到其它动态测量系统。     

涡轮叶片综合冷却效率实验研究

为了研究气冷涡轮叶片综合冷却效率及其影响因素,采用红外热像仪对叶片表面温度场进行了测量,同时在叶片中截面布置了15支热电偶用于校准红外热像仪的测量结果,获得了叶片表面温度场分布以及流量比、温比和落压比对叶片综合冷却效率的影响规律.实验结果表明:叶片温度场分布受内部冷却和外表面换热共同影响,叶片前缘与叶尖处于较高温度状态...     

一个控制超强电离辐射抗性开关基因的研究进展

电离辐射广泛存在于地球和空间,会引起生物体内的DNA损伤,导致机体突变甚至死亡.生物体的DNA损伤响应对于稳定基因组的完整性至关重要.耐辐射奇球菌因其超强的DNA修复能力成为研究DNA损伤修复的模式生物之一.PprI-DdrO系统是近年来发现的一种新型且高效的损伤响应途径,PprI作为响应损伤的重要开关蛋白,通过酶切D...