分布假设及其对复合材料B基值的影响

简要介绍了以经验分布函数统计量为基础的一类先进拟合优度检验方法，分析了不同母体分布假设对复合材料B基值的影响，认为采用3参数Weibull分布拟合复合材料强度数据比较合理。     

相变热图技术在表面热流测量中的应用

本文详细地介绍了在中国空气动力研究与发展中心低密度风洞中，进行的相变热图技术的应用工作。实验模型是尖锥及球锥，实验条件是自由来流马赫数Ｍ∞＝１６，来流雷诺数Ｒｅ∞／ｍ＝０．５×１０５～２．０×１０５，来流滞止温度Ｔ０＝９４０Ｋ，滞止压力ｐ０＝０．３９ＭＰａ～１．１７ＭＰａ。实验结果与国外计算结果作了比较。最大相对偏差２６．０％。本文对实验结果作了误差分析，介绍了相变漆响应滞后分析的一些结果。同时本文还介绍了相变热固技术的原理及方法。     

气／固两相流测量系统

面粉机提粉管中有流动着的气体和面粉，称之两相流，采用由二个极板组成的电容器和电容－电压变换电路组成的电容式传感器测量管道中流动着的面粉密度。用压力传感器测量管道中的风压并计算出风速，由风速和测得的面粉密度可算出管道的面粉流量，根据流量大小，计算机可控制每个磨口的工作状态。     

跨声速涡轮平面叶栅密度场的测量

在人口马赫数M_1=0.4、雷诺数Re_b=7×10~5来流条件下的激波风洞中，用激光差分干涉仪获得了跨声速涡轮平面叶栅流场干涉图，利用叶栅流场的周期性条件，给出相应的密度场定量结果。并与用S_1流面流函数矩阵解的计算结果做了比较，规律基本一致。     

F2 layer response to geomagnetic disturbances in Eastern Asia under the low solar activity

In this paper, the peculiarities of ionospheric response to geomagnetic disturbances observed at the decay and minimum of solar activity (SA) in the period 2004–2007 are investigated with respect to different geomagnetic conditions. Data from ionospheric stations and results of total electron content (TEC) measurements made at the network of GPS ground-based receivers located within the latitude–longitude sector (20–70°N, 90–160°Е) are used in this study. Three groups of anomalous ionospheric response to geomagnetic disturbances have been observed during low solar activity. At daytime, the large-scale traveling ionospheric disturbances (LSTIDs) could generally be related to the main phase of magnetic storm. Quasi-two-days wavelike disturbances (WLDs) have been also observed in the main phase independent of the geomagnetic storm intensity. Sharp electron density oscillations of short duration (OSD) occurred in the response to the onset of both main and recovery phases of the magnetic storm in the daytime at middle latitudes. A numerical model for ionosphere–plasmasphere coupling was used to interpret the occurrence of LS TIDs. Results showed that the LSTIDs might be associated with the unexpected lifting of F2 layer to the region with the lower recombination rate by reinforced meridional winds that produces the increase of the electron density in the F2 layer maximum.     

The subauroral electron density trough: Comparison between satellite observations and IRI-2007 model estimates

We compare electron density predictions of the International Reference Ionosphere (IRI-2007) model with in situ measurements of the satellites CHAMP and GRACE for the years from 2005 to 2010 over the subauroral regions. The electron density between 58° and 68° Mlat are considered. The trough region Ne peaks during local summers and attain the valley during local winter. Around −100°E and 60°E, two larger electron density sectors features can be seen in both hemispheres during all three seasons, which attributed to the electron extending from middle latitude to trough region. From 2005 to the beginning of 2010, the model overestimates the trough region Ne by 20% on average and the decrease of Ne in this region can also be seen during the last solar minimum. In the southern hemisphere, the model prediction shows quite well consistence with the observation during all three seasons while the huge difference between observations and model estimation implies that the IRI-2007 model needs significant improvement to predict better the trough region in northern hemisphere.     

高频高稳恒温晶体振荡器设计

本文采用低频高稳振荡与低噪声倍频相结合的方法,并进行精密控温设计,研制了一种高频高稳恒温晶体振荡器,输出频率为100MHz,短期频率稳定度可以实现2.68E-13/s,2.54E-12/100s,老化率优于7E-11/d,谐波优于-50dBc。经随机振动、冲击和温度冲击等环境试验考核,晶振试验前后频率变化均小于±5E-9,可以很好地满足多领域应用对高频高稳定信号源的需求,可靠性高,有利于简化系统构成,缩小设备体积。     

射线照相检测辐射场的黑度分布及影响因素

文章从射线强度分布、胶片感光原理推导了辐射场的黑度分布近似公式,给出了不同透照参数下相对黑度与辐射角的变化曲线,分析了透照参数对黑度分布均匀性的影响.通过实验测量,验证了理论结果.     

7715D高温钛合金及其与推进剂的相容性试验

介绍了Ｔｉ－Ｓｎ－Ｚｒ－Ｎｂ－Ｍｏ－Ｓｉ－Ｃｅ系合金７７１５Ｄ高温钛合金的研制过程。７７１５Ｄ分别在Ｎ２Ｏ４及甲基肼液体中进行的浸蚀２２３２ｈ的相容性试验。结果在Ｎ２Ｏ４及甲基肼中的腐蚀速率分别为４×１０－４ｍｍ／ａ及１×１０－４ｍｍ／ａ，均优于航天工业总公司的一级相容性标准。由７７１５Ｄ高温钛合金制作的ＤＦＨ－３大型广播通信卫星的远地点发动机已通过多台次的地面试车和长程高空模拟试牢，其中两台长程高空模拟试车均超过１８０００ｓ，发动机设计研制单位结论为７７１５Ｄ钛合金能满足该发动机地面试车及长程高空模拟试车的要求     

影响天线高仰角跟踪性能的因素分析

雷达或遥测系统大多采用方位－俯仰型天线座，这样方位支路跟踪时，原理上需要引入正割补偿，且补偿系数随着俯仰角的提高而增大。引入正割补偿后将对天线高仰角时的跟踪性能产生影响。迄今为止的有关著作只对其中部分因素进行了论述。本文对这些因素进行了全面分析，并以实际目标飞行数据说明，在不同条件下，主要影响因素也会不同。