高速帧转移型面阵CCD器件的时序设计

介绍了512×512高速帧转移面阵CCD器件时序设计的方法。在分析器件结构和时序关系的’基础上,确定了时序设计的主要参数,并利用复杂可编程逻辑器件（CPLD）EPM7256AETC100—5实现了CCD器件工作所需的各种时序信号。通过时序仿真证明,设计方法正确可行,运行稳定。     

YH-1火星探测器设计及研制进展

介绍了中国首颗YH-1火星探测器的任务功能、组成和主要技术指标。给出了探测器设计中的火星探测超低温适应、深空探测自主姿态确定与控制、超远距离通信、休眠唤醒和剩磁控制等关键技术,以及相应的解决途径。试验和验证结果表明：YH-1火星探测器的设计满足火星探测特殊环境的任务要求。其设计和试验技术可直接用于我国其他深空探测项目,为后续深空探测积累了经验。     

Operation and Application of A, B Satellites for Environment and Disaster Monitoring and Forecasting

Environment and disaster monitoring and forecasting small satellite constellation A and B satellites (HJ-1-A, B) are called "environment and disaster reduction satellites A and B' for short. The constellation adopts a 10:30 LT sun-synchronous circular orbit, with orbit altitude of 649 km. HJ-1-A and HJ-1-B are distributed with a phase difference of 180o in the same orbital plane, so as to enhance the time resolution of earth observation. The satellites have orbit maintenance capability, the lifetime is 3 years. Both satellites adopt CAST968 platforms. Two wide-coverage multispectral CCD cameras with resolution 30 m and width 700 km, a super-spectral imager with resolution 100 m and width 50 km as well as a data transmission subsystem of 120 Mbit/s are deployed on HJ-1-A, which also carries Ka communication testing equipment of Thailand. HJ-1-B has two wide-coverage multispectral CCD cameras (the same as satellite A), one infrared camera with resolution 150 m and width 720 km and a data transmission subsystem of 60 Mbit/s. The coverage period of the wide-coverage multispectral CCD camera is 48 hours. The revisit period of super-spectral imager is 96 hours and the coverage period of infrared camera is 96 hours.      

自动化测试系统在环境减灾-1A、1B卫星中的应用

在环境减灾-1A、1B（HJ-1A、1B）卫星的研制中,双星并行电性能综合测试是一个非常复杂和细致的过程,为此应用了卫星自动化测试系统,实现了测试信息的集中管理、测试数据的综合利用和测试流程的自动化,提高了测试工作的效率和质量。文章介绍HJ-1A、1B双星并行自动化综合测试系统,主要阐述测试实时数据库、自动化测试控制台、参数自动化监视软件等。     

基于混合算法的涡轴发动机稳态性能仿真模型

以自由涡轮式涡轴发动机为研究对象,建立了涡轴发动机的稳态性能仿真模型,提出了基于天牛须算法和N+1点残量法的求解发动机模型的混合算法(BAS-N+1混合算法),利用发动机台架试车数据对仿真计算结果进行了验证。结果表明,该稳态性能仿真模型各参数的求解误差在3%以内。与PSO-N+1混合算法相比,BASN+1混合算法求解精度更高,收敛更快。BAS-N+1混合算法既保留了智能算法对初猜值误差的包容性,也拥有接近经典迭代算法的收敛速度和精度,能够实现涡轴发动机稳态仿真模型的高精度大范围快速收敛。     

天琴一号卫星加速度模式无拖曳控制

结合卫星加速度模式无拖曳控制系统一般组成、各环节典型模型、常见控制器及天琴一号空间惯性基准建立试验卫星的采样周期与控制周期,着眼于工程实际问题的挖掘与解决,重点阐述了该卫星CIC滤波器组频响特性等效、加速度模式无拖曳控制系统稳定裕度及残余加速度指标分析与综合等技术内容。研究表明,多周期离散系统真实稳定裕度难于准确预测;积分系数是决定PSD指标的关键参数;抗混淆滤波器是提升时域残余加速度指标的关键环节,且有利于抑制高频数据在PSD低中频段的高频折叠;在未引入抗混淆滤波器的情形下,频域指标统计应以进入控制器的残余加速度数据为准。在轨飞行试验结果与仿真结果基本吻合。     

Spatial asymmetry in topside ion density and vertical E × B plasma drift velocity within 75°E–95°E

The ion density measured by the Ionospheric Plasma and Electrodynamics Instrument (IPEI) on board the ROCSAT -1 over the 75°E and 95°E meridian at 600km altitude has been utilized to examine the latitudinal and longitudinal distribution within the Indian sector, in particular, the north-south and east-west asymmetries of the equatorial ionization anomaly (EIA). A longitudinal gradient in ion density at 600?km higher towards 95°E develops during the noontime and afternoon hours when the EIA is at its peak. The density gradient persists till evening hours when pre-reversal enhancements occur. The vertical E?×?B plasma drift velocity measured simultaneously by ROCSAT -1 for the same space-time configuration has also been studied. In addition to diurnal, seasonal and solar activity variations in E?×?B drift velocity, the longitudinal gradient is also observed. The EIA at the altitude of 600?km peaks at different latitudes and are mostly asymmetric about the magnetic equator. From midnight till 0800 LT, the ion density across the equator is nearly uniform in the equinoxes. But in the solstices, the density exhibits a north-south gradient. In the June solstice, density is higher in the northern hemisphere and decreases gradually towards south. The gradient in density reverses in December solstice. Normally, the EIA peaks within 1200 LT and 1600 LT while around 2000 LT, pre-reversal enhancement of ionization occurs affecting the EIA evening structure. The strength of the EIA also exhibits seasonal, year-to-year and hemispheric variations. The longitudinal asymmetry of drift velocity along 75°E and 95°E longitude sectors is the contributing factor behind the observed longitudinal asymmetry in ion density. Significant positive correlation between the strength of the EIA and E?×?B drift is observed in both longitudes.     

Upwards migration phenomenon on molten lunar regolith: New challenges and prospects for ISRU

As part of our research on the feasibility of producing commodities from lunar regolith by thermal-driven processes with minimal terrestrial precursors we need to characterize, reproduce, and understand thermophysical properties of the molten regolith still unforeseen under the lunar vacuum conditions at a scalable sample size. Two unanticipated phenomena, apparently caused by lunar melt’s surface tension under vacuum, have been revealed in our research work, vacuum void formation and upwards migration. In this paper we present our findings and thinkable explanation on the upwards migration phenomenon experimentally observed and consistently replicated as JSC-1A lunar regolith simulant melted at high vacuum. Upwards migration of molten lunar regolith will make future lunar ISRU’s melting processes both challenging as molten bulk material would migrate upwards along the container’s walls, and also promising on new opportunities for alternative ISRU’s sustainable processes as regolith’s upwards migration takes place in uniformed thin-film pattern. Among the potential ISRU’s processes that might use controlled thermal thin-film-based migration without the necessity of terrestrial precursors are production of feedstock for 3D printing, fractional separation of regolith’s component’s (O₂, metals, and alloys) via pyrolysis, film coating, purification of valuables solid crystals including silicon, and fabrication of key elements for microfluidic, and MEMS devices. Thermal upwards migration phenomenon on JSC-1A’s melt is formulated and explained by the authors as due to thermal Marangoni effect (also known as thermo-capillarity) in which temperature gradients within the melt’s bulk and along the crucible’s wall yield the surface tension large enough to supersede the gravitational force and yield the experimentally observed upwards thin-film migration. As far as the authors know, upwards thermal migration of molten JSC-1A (or other lunar simulant regolith) under vacuum has not been reported in the literature. A thermal mathematical model accounting for thermal Marangoni effect on molten JSC-1A agrees with what experimentally was observed, the formation of the meniscus on the melt-wall surface interface along with an incipient upwards migration in thin-film pattern along the crucible wall that, according to the model, experiences large temperature gradient, an important factor to trigger the thermal Marangoni effect along with the fact that surface tension of the molten lunar regolith material is temperature dependent.     

XPNAV-1卫星先期发布数据的计时分析

本文处理了XPNAV-1先期公布的35组Crab脉冲星的观测数据,采用离散傅里叶变换(DFT)方法得到脉冲到达时刻(TOA)及其测量精度。利用英国Jordrell Bank发布的Crab脉冲星星历与美国JPL发布的DE200历表,得到的拟合前计时残差均方根(RMS)为1.14 μs,且不存在系统性趋势,从而验证了XPNAV-1观测数据的有效性。同时,得到了该观测数据时间段内Crab脉冲星的X射线和射电波段之间的零点相位差为0.04。本文还给出了建立脉冲轮廓时子相位间隔N的取值与计时残差的RMS之间的关系。     

固体火箭发动机动力相似准则研究

本文以小发动机模拟大发动机为目标，探讨固体火箭发动机的动力相似准则，首先把动力相惟问题归结为燃烧室，喷管一体化流动的相似问题，通过对全三维Ｎ－Ｓ方程所进行的无量纲化分析，在几何相似的前提下，得到固体火箭发动机动力的流上似准则，再通过对控制方程的单值性条件所进行了无量纲化分析，得到了在初始状相似条件下的燃速相似准则；另外还得到了飞行条件相似、燃烧温度相似以及普朗特数相等。并进一步对这些准则进行了分析