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101.
102.
In wide-swath missile-borne synthetic aperture radar (SAR) imaging, the range-variant residual phase modulation, which is introduced by the presence of trajectory deviations, will seriously degrade the focusing quality of the final image. To deal with this problem, a motion compensation approach for missile-borne SAR is proposed. In the approach, the signal model of motion error for diving movement is established. Then, according to the inertial navigation system (INS) information, the range-variant residual Doppler rates of the echoes are extracted by using the Doppler rate estimation, on the basis of which the corresponding phase error can be calculated and compensated. Simulation results show that, by using the proposed approach, the influences of the motion error on focusing are greatly reduced with the well focused image obtained. 相似文献
103.
针对输电线路测量中,不能直接精确测定钢管杆中心坐标的问题。提出了使用三距离交会的测量方法,以及利用网络RTK配合手持电子测距仪,快速测得钢管杆附近三个点的坐标以及相应距离。针对不同观测数据编写了相应的VB程序,提高了工作效率。 相似文献
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107.
Kenneth T. Leong James C. Booth J. H. Claassen 《Journal of Superconductivity and Novel Magnetism》2006,19(7-8):637-648
We introduce a novel transmission-line method for determining the penetration depth in thin high-temperature superconducting
(HTS) films. The method is based on the accurate measurement of the inductance per unit length of a superconducting coplanar-waveguide
(CPW) transmission line fabricated on the HTS sample. Using the experimentally obtained inductance per unit length, we interpolate
the penetration depth from a table of numerically determined values of inductance (per unit length) as a function of penetration
depth, calculated from a coupled transmission-line model. A novelty of our procedure is the utilization of the multiline thru-reflect-line
(TRL) method and the calibration-comparison method to accurately determine the inductance per unit length of the superconducting
transmission line. By measuring different CPW geometries patterned onto the same thin-film sample, we can verify our penetration
depth values. We demonstrate this technique by extracting the penetration depth for several different HTS films at 76 K. Estimated
uncertainties in the extracted penetration depth are also provided.
Contribution of an agency of the US government not subject to copyright. 相似文献
108.
A digital spectral method of the maximum harmonic for processing laser Doppler vibration meter signals from a surface vibrating
according to a harmonic rule is analyzed. A digital model for this signal in the presence of additive and multiplicative noises
is suggested. Examples are given for the effect of signal discretization frequency on the error of determining vibration amplitude.
__________
Translated from Izmeritel’naya Tekhnika, No. 9, pp. 42–45, September, 2006. 相似文献
109.
Nanocluster beam technology combined with conventional sputtering was used to fabricate FePt–SiO2 nanocomposite films in this present work. The post-deposition annealing affected the final particle size and size distribution of FePt nanoclusters. The effects of both volume fraction of SiO2 matrix and annealing temperature on magnetic and microstructural properties were studied. Partial ordering, grain growth and agglomeration of FePt particles in FePt–SiO2 nanocomposite films occurred during annealing. A higher volume fraction of SiO2 matrix was effective in suppressing diffusion of atoms and magnetic exchange coupling of FePt grains. Excessive SiO2 however resulted in a lower degree of FePt ordering and thus lower coercivity. 相似文献
110.
近一个世纪以来,对黑体相对论温度变换的讨论一直在进行着。其中最具代表性的变换是在上世纪六十年代,由R.N.Bracewell等人以从实验发现的3K宇宙背景辐射为基础、从与实验符合很好的Plank黑体辐射公式出发,用不同方法得到的变换式T=T0 相似文献