Quick determination of included angles distribution for miscut substrate

A simple method which can be performed with general laboratory facility is described for quickly determining the included angles distribution (including miscut angle) between the crystal plane and sample plane for a miscut substrate. This method is based on the rocking curve measurement of High-resolution X-ray diffraction (HRXRD). After easily measuring and calculating values of two included angles (θ₁ and θ₂) between the crystal plane and sample plane at two arbitrary mutually perpendicular azimuths of the sample plane by HRXRD, all included angles at arbitrary azimuths of the miscut substrate can be quickly calculated. Further, the value of miscut angle (θ_max) can be determined and its specific azimuth position on sample plane can be also easily found. Besides, since original azimuthal measurements of θ₁ and θ₂ may be situated on different positions of the sample plane, the possible condition is finally classified as four types. And then, the curves of miscut angle and azimuthal orientation under four different conditions are described in detail, respectively and their computational formulas are also distinguished carefully.     

An automatically paired two-dimensional direction-of-arrival estimation method for two parallel uniform linear arrays

In two-dimensional (2-D) direction-of-arrival (DOA) estimation, paring the azimuth and elevation angles of multiple sources is an important issue. In this letter, we propose a new automatically paired 2-D DOA estimation method by designing the geometry of two antenna subarrays and using the propagator method (PM). A special geometry between two parallel uniform linear arrays (ULAs) with a position displacement on the axial direction is proposed to facilitate the elevation and azimuth pairing and estimation. The simulation results have shown that the proposed method can achieve the same 2-D DOA estimation performance as the existing methods, while the complexity is reduced considerably.     

Novel approach based on deramping technique for squinted sliding spotlight SAR imaging

This paper investigates a novel approach based on the deramping technique for squinted sliding spotlight Synthetic Aperture Radar (SAR) imaging to resolve the azimuth spectrum aliasing problem. First of all, the properties of the azimuth spectrum and the squint angle impacts on the azimuth spectrum aliasing problem are analyzed. Based on the analysis result, an operation of filtering is added to the azimuth preprocessing step of traditional Two-Step Focusing Approach (TSPA) to resolve the azimuth folding problem and remove the influence of the squint angle on the azimuth spectrum aliasing problem. Then, a modified Range Migration Algorithm (RMA) is performed to obtain the precise focused image. Furthermore, the focused SAR image folding problem of traditional TSPA is illuminated in this paper. An azimuth post-processing step is proposed to unfold the aliased SAR image. Simulation experiment results prove that the proposed approach can solve the spectrum aliasing problem and process squinted sliding spotlight data efficiently.     

施耐德工程型变频器在船舶全回转推进器上的应用

变频驱动的船舶全回转推进器大大增强了船舶的机动性。本文讨论了全回转推进器对变频器调速系统的特殊要求,主要是大电流输出、散热、防护、谐波以及功率限制功能等问题。同时,以施耐德电气的工程型柜式变频器为例,介绍了如何设计变频调速系统以满足船用环境以及全回转推进器的特殊要求。     

玫瑰线图形扫描方位信息的计算及误差分析

简要介绍了玫瑰线图形扫描，分析了如何使玫瑰线图形扫描系统的基准统一，解决了目标方位信息的计算问题，然后对种扫描系统的误差源逐一进行分析，得出各自对系统的影响，最后，求出系统总误差。     

Power output analysis of transparent thin-film module in building integrated photovoltaic system (BIPV)

The power output of PV module was characterized depending on incidence angle and the azimuth using a transparent thin-film solar cell in a mock-up model at various slopes to the south, as a building integrated photovoltaic system. Simulated data was also evaluated to determine the influence of the inclined angles and the azimuth on the power performance of the PV module. The experimental and computed data fitted comparatively well through the relative error estimation after calibration. It was found that the PV module with a slope of 30°, facing south, provided the best power performance according to an annual power output, producing about 2.5 times higher power output than that with the vertical module. Furthermore, the PV module facing south showed higher power output than that to the east. The varying power output of the PV module with inclined angles can be explained by the impact of the incidence angle modifier of the glass on the PV module. Specifically, the increased inclined slope of the PV module resulted in the reduced solar energy transmission, which producing a significant reduction of power output for the PV module with a slope over 70°.     

合成孔径雷达的噪声干扰

合成孔径雷达是一种成像雷达,在距离上和方位上都采用脉冲压缩技术,因此,具有极高的分辨力。本文通过给出的合成孔径雷达干扰方程,提出对一部具有两种不同匹配滤波器的雷达实施噪声干扰时,应采用两种不同带宽的噪声干扰信号,以及实施噪声干扰的方法。     

基于TS-201的三坐标雷达点迹处理器的设计与实现

文中根据三坐标雷达波束空间分布的特点,采用"小滑窗检测"作为目标检测准则,"方位上求质量中心、距离上按峰值搜索,仰角上峰值搜索测角"作为目标点迹凝聚准则设计了三坐标雷达点迹处理器,并在八片TS201高性能处理器平台上实现。     

一种新的空间信号三维参数可分离估计方法

本文基于非均匀线性阵列和阵元输出信号时延提出了一种新的多个空间窄带信号频率、方位角和仰角三维参数可分离估计方法。信号频率估计是ESPRIT算法实现的．信号方位角和仰角是两个一维MUSIC算法完成的．该方法可以并行实现以进一步增强其实时性．计算机模拟证实了此方法的有效性．     

弹道导弹诸元计算中方位角初值的精确确定

方位角初值的确定对诸元计算的快速性有很大的影响.讨论了3种初值确定方法:不考虑地球旋转的初值确定,考虑地球旋转的初值确定和考虑主动段弹道变形的初值确定.其中考虑主动段弹道变形的初值确定方法是在对弹道特性分析的基础上首次提出的.通过算例分析,考虑主动段弹道变形的方位角初值在所有情况下都能给出较好的估计.