高超声速钝锥模型及其尾迹红外辐射实验研究

介绍了利用InSb红外辐射计在弹道靶上测量底部直径为10mm、半锥角和头部半径分别为9°、2.2mm(模型A),8°、0.6mm(模型B)的两种非烧蚀钝锥模型及其尾迹的红外辐射.模型速度大于6km/s,飞行环境压力约4.8kPa,红外辐射测量波段为1~3μm、3~5μm.结果表明:非烧蚀钝锥模型头身部红外辐射远大于尾迹红外辐射,在相同飞行速度和环境压力条件下,模型A产生的红外辐射比模型B产生的红外辐射强.     

红外增强器辐射特性的测试和实验研究

本文对某靶机拖靶的红外增强器的红外辐射特征进行了实验研究,将红外增强器作为点源目标,对几种不同结构形式,在不同工作状态下,进行了地面现场实验测试。文中简要介绍了所使用的仪器和组合的红外测试系统,着重论述了红外增强器的辐射光谱特征、辐射能随时间和空间的分布情况、在多种工作状态下的表观有效红外辐射强度等红外辐射特征的实验测试方法,并对实验结果进行了分析。 实验表明:所测数据具有较好的重复性,相关参数具有明显的紧密相关性,其结果是可信的,为研制新型红外辐射源,提供了一种可供借鉴的探测系统和探测技术。     

MONITORING OF ENERGETIC PARTICLE ENVIRONMENT INSIDE THE CHINA-BRAZIL EARTH RESOURCE SATELLITE

On 14 October 1999, the Chinese-Brazil earth resource satellite (CBERS-1) was launched in China. On board of the satellite there was an instrument designed at Peking University to detect the energetic particle radiation inside the satellite so the radiation fluxes of energetic particles in the cabin can be monitored continuously. Inside a satellite cabin, radiation environment consists of ether penetrated energetic particles or secondary radiation from satellite materials due to the interactions with primary cosmic rays.Purpose of the detectors are twofold, to monitor the particle radiation in the cabin and also to study the space radiation environment The data can be used to study the radiation environment and their effects on the electronics inside the satelhte cabin. On the other hand, the data are useful in study of geo-space energetic particle events such as solar proton events, particle precipitation and variations of the radiation belt since there should be some correlation between the radiation situation inside and outside the satellite.The instrument consists of two semi-conductor detectors for protons and electrons respectively. Each detector has two channels of energy ranges. They are 0.5-2MeV and ≥2MeV for electrons and 5-30MeV and 30-60MeV for protons. Counting rate for all channels are up to 104/(cm2@s)and power consumption is about 2.5 W. There are also the additional functions of CMOS TID (total integrated dose) effect and direct SEU monitoring. The data of CBMC was first sent back on Oct. 17 1999 and it's almost three years from then on. The detector has been working normally and the quality of data is good.The preliminary results of data analysis of CBMC not only reveal the effects of polar particle precipitation and radiation belt on radiation environment inside a satellite, but also show some important features of the geo-space energetic particle radiation.As one of the most important parameters of space weather, the energetic charged particles have great influences on space activities and ground tech nology. CBMC is perhaps the first long-term on-board special equipment to monitor the energetic particle radiation environment inside the satellite and the data it accnmulated are very useful in both satellite designing and space research.     

SPACE LIFE SCIENCE IN 2000-2001

Chinese scientists studied some of the problems in the field of space life science and achieved success in the area during 2000-2001. Space biological experi ments were carried out in the orbit and the results of ground studies on protein crystallization, space radiation, space motion sickness were introduced in this paper. The influences of simulated weightlessness on the brain-function, the car diovascular, endocrine hormones, immunity, skeletal and muscle systems were presented. In addition, gravity medicine and space environment medicine, as well as countermeasures to space deconditioning, such as the traditional Chinese medicine, were also reported.     

Conditional sea surface statistics and their impact on geophysical sea surface parameters retrieved from SAR altimetry signals

In this study we present an analytical formulation of synthetic-aperture radar (SAR) altimetry signals including narrow banded nonlinear wave fields and conditional statistics between wave elevation displacements, horizontal wave slopes and vertical wave particle velocities. Considering the wave elevation displacements coskewness with respect to horizontal slopes leads to an analytical formulation of the electromagnetic bias within a SAR-mode altimeter stack. This formulation can be either parametrized by the significant wave height (SWH) and mean wave steepness, or in terms of the variance of vertical wave velocities. The effect of conditional vertical wave particle velocity variances with respect to the observed horizontal wave slopes close to nadir incidence angles leads to an effective reduction of the azimuth blurring of SAR-mode stacks. We present here a formulation of this effect by examining JONSWAP ocean wave spectra. In most cases this effect reduces the azimuth blurring by 10% to 30%. Additionally we investigate the effect of a nonlinear wave elevation displacement probability density function (PDF) on estimated geophysical parameters. We were able to show that including an elevation displacement skewness of 0.13 improves significantly the SWH consistency between altimetry and ECMWF Reanalysis v5 ERA5 results.All of these effects are validated with respect to ERA5 model data in the North East Atlantic region and in situ data located in the German Bight and Baltic Sea.The developed model can be used in both SAR and conventional altimetry retrackers.     

某小型无人机中长波辐射特性测量及辐射强度反演

随着“自杀式”无人机集群的饱和式攻击在战场上发挥巨大威力,如何有效拦截是各国近年来研究的重要方向,而红外探测是最热门也是最高效的探测拦截手段之一。为此,开展某典型无人机目标中长波红外探测试验,获取典型某无人机目标辐射特性数据,完成中长波红外辐射强度反演。同时,考虑环境变化对红外探测的影响,为使用红外探测手段完成无人机目标拦截提供实测效果演示。本文研究结果可作为论证中长波对无人机目标探测差异的依据,以支撑探测体制的选择。     

某类跨大气层飞行器全航程红外辐射特性分析

针对某类跨大气层飞行器飞行过程中需要进出大气层,且飞行速度跨度大等特点,建立了不同空域、不同飞行速度下的机体头部受热模型。当在大气层内飞行时分别使用经验公式和Lees公式计算马赫数小于5和大于5时头部受热情况,当在大气层外飞行时建立了考虑太阳直射、地球反照和地球红外加热情况下的受热模型。利用普朗克定律得到了相同温度下不同波段的红外辐射能量占比情况。最后利用本方法对某类跨大气层飞行器进行了温度和红外辐射计算,得到的计算结果能够大致反映全航程头部温度和红外辐射变化情况。     

原子氧和紫外线对聚酰亚胺综合作用数值模拟

在建立数学物理模型的基础上,对低地球轨道环境和地面试验环境下有无保护涂层的聚酰亚胺所受原子氧冲蚀及紫外线的综合作用进行了数值模拟,获得了具有工程应用价值的计算结果,并讨论了数学物理模型中各参数对基蚀曲线形状的影响.从数值模拟结果与美国太空试验结果的比较可以看出,得出的数值模拟的结果是正确的,对航天器设计具有重要的指导意义.     

异型封闭腔辐射几何学问题

讨论了解决异型封闭腔辐射几何学问题的几种方法:异型封闭腔内,表面间可见性的判断方法;优化异型封闭腔角系数计算的方法;确定异型封闭腔内定向辐射的壁面辐射源的方法.计算了两种结构喷管封闭腔内的角系数,并从角系数的互换性和完整性定理验证了方法的正确性和有效性,为异型封闭腔的辐射计算解决了几何问题.     

Asymmetric precipitation in a coronal loop as explanation of a singular observed spectrum

Almost 10 years of solar submillimeter observations have shown new aspects of solar activity, such as the presence of rapid solar spikes associated with the launch of coronal mass ejections and an increasing submillimeter spectral component in flares. We analyse the singular microwave–submillimeter spectrum of an M class solar flare on 20 December, 2002. Flux density observations measured by Sun patrol telescopes and the Solar Submillimeter Telescope are used to build the radio spectrum, which is fitted using Ramaty’s code. At submillimeter frequencies the spectrum shows a component different from the microwave classical burst. The fitting is achieved proposing two homogeneous sources of emission. This theoretical fitting is in agreement with differential precipitation through a magnetically asymmetric loop or set of loops. From a coronal magnetic field model we infer an asymmetric magnetic structure at the flare location. The model proposed to quantify the differential precipitation rates due to the asymmetry results in a total precipitation ratio Q₂/Q₁≈10⁴–10⁵, where Q₁(Q₂) represents the total precipitation in the loop foot with the high (low) magnetic field intensity. This ratio agrees with the electron total number ratio of the two sources proposed to fit the radio spectrum.