高速摄影技术在三维位移测量中的应用

提出了用高速摄影技术准确测量三维位移的新方法。该方法利用一只测量基准，使两台高速摄影机的拍摄方向相互垂直或成一定角度，并使所有的测点都在拍摄范围内。从摄影胶片上点的运动求出测点的三维坐标。实验结果表明：该方法的测量精度较高，适用于测量大梦位移的时间历程。     

Effects of eccentricity of the reference orbit on multi-tethered satellite formations

The paper discusses the relevance of eccentric reference orbits on the dynamics of a tethered formation, when a massive cable model is included in the analysis of a multi-tethered satellite formation. The formations examined in this study are hub-and-spoke (HAS) and closed-hub-and-spoke (CHAS) configurations for in-plane and Earth-facing spin planes. Stability of the formations is studied by means of numerical simulation, together with the evaluation of the effects of eccentricity on tether elongation, agents relative position, and formation orientation and shape.     

开环光纤陀螺的数字接口研究

为了提高开环光纤陀螺(FOG)的性能,对它的输出进行了分析并建立了相应的数学模型.在此基础上设计了一种数字化接口,该接口是一种小型的微控制系统,由增益可控的A/D转换器和相应控制软件组成并具有自动分档功能,它除了将开环FOG的模拟输出数字化外,还实现了数字输出的线性化.利用一种全保偏开环FOG进行了实验研究,在采用这种接口后,FOG的输出在±100°s范围内,其标度非线性值可由10－2量级减小到10－4量级.      

一个高性能单反射面紧缩场

介绍了一个单反射面紧缩场,其反射面实体由多块面板拼装而成.单块面板成形基于"点阵钉模、真空负压、金属蜂窝"精密成形工艺,平均精度达到25μm(rms),拼装后总体形面精度达到40μm(rms).通过优化电气布局、边缘设计和馈源设计,该紧缩场具有优良电性能.给出了该紧缩场在39GHz时电性能实测曲线.      

一种超高分辨率机载聚束SAR两维自聚焦算法

受运动参数测量误差和大气扰动等因素影响,合成孔径雷达(SAR)图像通常会发生散焦,利用自聚焦对散焦的SAR图像进行后处理是一种有效的重聚焦手段。传统的自聚焦算法都只是针对方位一维相位误差的估计和补偿。随着成像分辨率的提高,自聚焦时残留距离徙动的校正成为SAR成像面临的一个新挑战。本文推导得到了极坐标格式算法处理后残留距离徙动和方位相位误差的解析表达式,分析了两者之间的内在关系,并利用该关系,提出了一种能够同时进行残留距离徙动和方位相位误差补偿的两维自聚焦算法。实测数据处理结果表明,在残留距离徙动效应不可忽略的条件下,该方法能够极大地改善原有自聚焦算法的聚焦性能。     

基于全局气动优化方法的跨声速叶栅气动优化

提出了适用于叶栅三维气动设计优化的全局自动气动优化方法.对NASA Rotor 37转子叶栅进行了气动优化设计.利用该叶栅的试验数据校核了计算流体(CFD)程序的可靠性.以等熵效率最高为目标函数,在满足流量约束和总压比约束的条件下,完成了跨声速叶栅的气动优化设计.优化叶栅的等熵效率提高了1.66%,具有优秀的气动性能和变工况性能.优化结果表明,通过优化三维跨声速叶栅的型线和径向基迭方式,可以有效的减小跨声速叶栅的激波损失.      

雷达探测距离的区间估计

雷达探测距离是雷达发射功率、频率、接收信号功率等这些不确定参数的函数。以区间数学为基础,将这些不确定参数描述为区间变量,借助一阶泰勒级数,提出了近似估计雷达探测距离的区间分析方法。区间分析方法降低了以往处理不确定问题概率方法需要知道不确定参数均值、方差或概率分布密度等详细统计信息的要求,只要求知道不确定信息所在的边界,而且计算量少。通过算例与概率分析方法相比较,表明了区间分析方法的可行性和优越性。     

Deramp range migration processing for space-borne spotlight synthetic aperture radar

The deramp range migration algorithm (DRMA) for space-borne spotlight synthetic aperture radar (SAR) is presented, which is based on the two-step algorithm and range migration algorithm. The presented algorithm combines the advantages of SPECAN algorithm and range migration algorithm. Firstly, the presented algorithm performs a bulk azimuth raw data compression to achieve a pixel spacing no larger than the expected azimuth resolution of the fully focused image. Therefore, the azimuth spectral folding phenomenon is overcome. Secondly, the residual and precise focusing of the synthetic aperture radar data is achieved by applying the range migration algorithm. The space-borne SAR focusing parameters’ computation is also described in the paper. At the end of this paper, results are presented which confirm the validity of the presented algorithm.     

发动机零部件稳态应力计算的状态函数法

An opti mization process is used to redesign blades of a high-pressure compressor.An artificial neural network (ANN) method is coupled to Navier-Stokes solvers and is applied to three different redesigns.A newrotor blade of a transonic compressor is designed by modifying thick, stacking line andinlet angle using a 3Dapproach, with a significant efficiencyi mprovement at the design point.The off-design behavior of this new compressor is also checked afterwards, which shows that the whole performance of the inlet stage is improved over a wide range of mass flow.The losses are reduced, proving the good performance of the opti mum.The whole results indicate that the opti mization method can find i mproved design and can be integrated in a design procedure.      

海南地区强磁暴期间强区域扩展F事件研究

利用2004年海南DPS-4数字测高仪观测到的强区域扩展F(SSF)数据,分析研究了5个强磁暴(Dst＜-100 nT)事件期间海南SSF的响应特征.结果发现,在海南地区,5个强磁暴事件中有3个磁暴Dst最小值位于2200-0200 LT之间,在磁暴主相及恢复相初期均出现了SSF现象,这种触发作用可能源于磁层直接渗透电场的作用,而另两个磁暴Dst最小值均发生在白天,一个SSF现象出现在磁暴的恢复相晚间,另一个SSF现象出现在超强磁暴的初相晚间,后者可能由该超强磁暴的急始造成的直接渗透电场所触发;5个强磁暴期间发生的SSF现象或者仅出现在午夜前,或者先出现在午夜前并持续到午夜后;同时,还就这些观测结果与Dabas等人有关磁暴对ESF影响的结论进行对比和讨论.