空间交会对接CCD光学成像敏感器光学特性

以辐射度量为标准,建立了CCD像机探测合作目标光功率模型以及功率方程,得到了所需合作目标光功率与CCD像机参数的制约关系,分析了CCD像机探测到光点所占像元数与传输距离之间的关系。用超焦距方法解决了CCD像机对有限远距离范围内工作时的成像清晰度问题,采用了像方远心光路设计解决了系统测量精度问题。研究了太阳光进入CCD像机视场和照射对接口反射后对CCD像机产生的影响。     

空间模拟电子辐照环境下聚四氟乙烯二次表面镜的损伤和衰退

文章介绍了在实验室模拟空间静电放电环境下聚四氟乙烯二次表面镜所受到的损伤和污染.通过光学和扫描电子显微镜检测出了13种不同类型的损伤;而喷溅表面污染物由俄歇谱仪进行分析.文章进一步阐明了导致聚四氟乙烯二次表面镜的严重衰退的环境条件,评估了损伤与未损伤二次表面镜在太阳光谱范围内的反射特性,并比较了这些试样和标准铝板的热性能.     

羽流光谱的原子辐射仿真

为对液体火箭发动机羽流光谱实验数据进行定量分析 ,通过建立高温气体下辐射传递模型 ,对1 Cr1 8Ni9Ti的理论光谱进行了仿真计算。结果表明 ,在路径一定的情况下 ,羽流中原子浓度较低时 ,可采用光学薄模型 ,原子浓度较高时 ,可采用光学厚模型     

检定几何量仪器标准器组测量不确定度评定

以标准线纹尺、小量块组、多面棱体、刻线样板、标准半圆球、渐开线样板检定／校准几何量光学仪器时,标准器组的测量不确定度评定。     

刘家峡右岸水电站模型试验的光路布置

使用二维激光多普勒测速仪（ＬＤＶ）对圆管中水注流进行测速时,对于窗口的设置、利用反射镜前向接收的方法和侧向接收方式等问题,本文进行了探讨,并总结了测量中的一些实际经验。     

Application of CCD drift-scan photoelectric technique on monitoring GEO satellites

Geosynchronous Earth Orbit (GEO) satellites are widely used because of their unique characteristics of high-orbit and remaining permanently in the same area of the sky. Precise monitoring of GEO satellites can provide a key reference for the judgment of satellite operation status, the capture and identification of targets, and the analysis of collision warning. The observation using ground-based optical telescopes plays an important role in the field of monitoring GEO targets. Different from distant celestial bodies, there is a relative movement between the GEO target and the background reference stars, which makes the conventional observation method limited for long focal length telescopes. CCD drift-scan photoelectric technique is applied on monitoring GEO targets. In the case of parking the telescope, the good round images of the background reference stars and the GEO target at the same sky region can be obtained through the alternating observation of CCD drift-scan mode and CCD stare mode, so as to improve the precision of celestial positioning for the GEO target. Observation experiments of GEO targets were carried out with 1.56-meter telescope of Shanghai Astronomical Observatory. The results show that the application of CCD drift-scan photoelectric technique makes the precision of observing the GEO target reach the level of 0.2″, which gives full play to the advantage of the long focal length of the telescope. The effect of orbit improvement based on multi-pass of observations is obvious and the prediction precision of extrapolating to 72-h is in the order of several arc seconds in azimuth and elevation.     

Multi-wavelength coordinated observations of ionospheric irregularity structures from an anomaly crest location during unusual solar minimum of the 24th cycle

The present paper reports coordinated ionospheric irregularity measurements at optical as well as GPS wavelengths. Optical measurements were obtained from Tiny Ionospheric Photometer (TIP) sensors installed onboard the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites. GPS radio signals were obtained from a dual frequency GPS receiver operational at Calcutta (22.58°N, 88.38°E geographic; geomagnetic dip: 32.96°; 13.00°N, 161.63°E geomagnetic) under the SCIntillation Network Decision Aid (SCINDA) program. Calcutta is located near the northern crest of Equatorial Ionization Anomaly (EIA) in the Indian longitude sector. The observations were conducted during the unusually low and prolonged solar minima period of 2008–2010. During this period, four cases of post-sunset GPS scintillation were observed from Calcutta. Among those cases, simultaneous fluctuations in GPS Carrier-to-Noise ratios (C/N_o) and measured radiances from TIP over a common ionospheric volume were observed only on February 2, 2008 and September 25, 2008. Fluctuations observed in measured radiances (maximum 0.95 Rayleigh) from TIP due to ionospheric irregularities were found to correspond well with C/N₀ fluctuations on the GPS links observed from Calcutta, such effects being noted even during late evening hours of 21:00–22:00 LT from locations around 40° magnetic dip. These measurements indicate the existence of electron density irregularities of scale sizes varying over several decades from 135.6 nm to 300–400 m well beyond the northern crest of the EIA in the Indian longitude sector during late evening hours even in the unusually low solar activity conditions.     

Experimental study on NOx emission correlation of fuel staged combustion in a LPP combustor at high pressure based on NO-chemiluminescence

Experimental investigations on NO_x emissions of a single-cup, Lean Premixed Prevaporized (LPP), module combustor were carried out at elevated inlet temperature and pressure up to 810 K and 2.0 MPa, close to the real operating conditions of aero-engine combustors. This LPP combustor adopts centrally staged fuel injections which could produce separated stratified swirling spray flame. In the NO_x emissions measurements, the ranges of dome equivalence ratio and fuel stage ratio were from 0.55 to 0.58 and 8% to 24%, respectively. The optical diagnosis on separated stratified swirling spray flame were carried out with fuel stage ratio changing from 15% to 30%. Therefore, NO* and OH* chemiluminescence images were obtained. The results show that NO_x emissions increase with the increase of the fuel stage ratio. And from the chemiluminescence images, the main flame and pilot flame are found weakly coupled. The pilot flame plays a significant role in NO_x emission production because of its higher adiabatic flame temperature. Based on the results of chemiluminescence optical tests, a new NO_x emission prediction model is proposed based on the Lefebvre’s single flame model. The estimate of local equivalence ratio of the pilot stage’s non-premixed flame is modified considering the characteristics of spray combustion, and a “PLUS” emission prediction model suitable for separated stratified swirling spray flame is obtained. Compared to the experimental data, the “PLUS” model exhibits a good prediction in a range of ±13% of deviation.     

On the optical variability of a be star,HDE 245770, — the optical counterpart of the transient X-ray pulsar A0535+26

Photoelectric WBVR observations of Be star HDE 245770=V 725 Tau, the optical counterpart of the transient X-ray pulsar A0535+26, having a pulse period of about 104 s, were conducted for more than 10 years. An irregular long-term optical variability of the star with amplitudes of the order of a few tenths of magnitude was found to be a usual phenomenon. In some cases rapid changes of the star's optical luminosity with a characteristic period of a few tens of minutes or a few hours, and an amplitude of several hundredths of magnitude in all the spectral bands used, which have practically coincided or correlated with the X-ray pulsar outbursts detected by X-ray satellites, were observed.Photoelectric recording of the optical flux from HDE 245770 were made in 1981–1982 with a time resolution of 1 second and 10 s, respectively, in theR spectral band (₀ 7000 Å) and in the narrowH -emission-line band (_1/2 75 Å) using a 48-cm reflector of High-Mountain Tien-Shan observatory of the Sternberg Astronomical Institute near Alma-Ata. An analysis of autocorrelation functions of the flux changes from object under study and a comparison with the star BD+26° 876 indicated the variability of luminosity of V 725 Tau in theR spectral band on a time scale of a few tens of second; this variability resembles shot noise with a characteristic time of stochastic bursts of about 15–20 s and their amplitudes of about a few tenths of a percent. InH -emission-line radiation autocorrelation functions and power spectra show quasiperiodic variability of luminosity of HDE 245770 with a characteristic period of about 100–150 s and an amplitude in the neighbour-hood of 0.5%. The latter result is not quite reliable because of not quite fine weather conditions during the observations; independent observations and check-up are required.     

航空航天复合材料结构健康监测技术研究进展

通过在线监测结构响应,实时掌握结构的健康状况,并在此基础上对可能发生的损伤和故障进行预报,以便能及时采取措施,保证复合材料结构的服役安全.综述了几种重要的结构健康监测方法的研究进展、应用场合与发展历程,包括:全局状态感知技术(光纤传感监测法)、全局损伤诊断技术(波传播损伤诊断法)、局部损伤诊断方法(机电阻抗监测法、真空比较监测法、智能涂层法等),讨论了复合材料结构健康监测传感器的安装方法.结合各种技术的发展历程和优缺点展望了航空航天复合材料结构健康监测技术的发展趋势.