共查询到19条相似文献,搜索用时 109 毫秒
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面向世纪之交的射电天文 总被引:1,自引:0,他引:1
立足于无线电电子科学技术和其它技术的发展,而诞生和成长起来的射电天文学已经走过了62年成果累累的历程,面临21世纪人类神经和自然技术包括天文学发展的挑战,射电天文学将迈出的新的步伐。本文拟在射电天文现状和讨论中计划的基础上对此给予评述和预测。 相似文献
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本文主要讨论利用射电进行对测天体确定天体在天球上的位置,或通过观测射电天体进行天文定位时,需要考虑大气折射的影响,并给出了观测天体射电的蒙气差ρ理论计算和修正方法。 相似文献
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从射电天文业务的发展历程出发,介绍了国际电信联盟划分给射电天文业务使用的无线电频率情况,梳理了射电天文业务干扰源的类型并提出了初步解决方法,此外还列举了国际电信联盟关于射电天文业务电磁兼容分析的决议书和建议书等。 相似文献
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韩金林 《电气电子教学学报》2002,24(5):1-4
天文学的研究完全基于对宇宙中天体电脑波辐射的探测和理解,电子学在各种探测过程和信号分析中起着不可或缺的作用。目前国内、国际所有的天文观测设备都必须配备一流的甚至独一无二的电子设备。射电天文学研究天体的无线电波。这里介绍电子在天文研究中的一些应用,特别是射电天文的测量方法,详细介绍探测和研究一种发射脉冲信号的天体(脉冲星)的具体方法。 相似文献
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超高稳定毫秒周期射电脉冲星的定时研究 总被引:4,自引:0,他引:4
文中介绍超高稳定毫秒周期射电脉冲星的定时研究的概况、基本理论、方法及应用前景。并指出接收测量方面关键的技术手段及解决方法。 相似文献
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我国计划6年后在贵州省建成世界最大单口径球面射电天文望远镜。为支持这一重要工程,12月16日,信息产业部无线电管理局在贵州召开会议,就村通工程频率与射电天文业务频率问髓进行调研、协调。 相似文献
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A. I. Efimov L. A. Lukanina A. I. Rogashkova L. N. Samozhaev I. V. Chashei M. K. Bird M. Pätzold 《Journal of Communications Technology and Electronics》2013,58(5):429-439
Experimental radio sounding data of the circumsolar plasma, recorded with the help of the Ulysses, Mars Express, Venus Express, and Rosetta spacecraft, have been systematically analyzed. These data were processed via spectral and correlation methods with the aim of detecting quasi-periodic frequency fluctuations. Integral wavelet spectra have been constructed for the purpose of identifying periodic radio frequency fluctuations at different periods. Comparative analysis of the methods for detecting the quasi-periodic disturbances of the radio frequency in the circumsolar plasma has been carried out. It is demonstrated that frequency fluctuations with periods of 1–80 min are observed regularly in radio sounding experiments of the solar wind plasma. 相似文献
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With long-term ionosonde records from 1947 to 2001 at Chong-qing, China, we show long-term trends of the ionospheric parameters, the critical frequencies of E-layer foE, F1-layer foF1 and F2-layer foF2, the E-layer height h'E, and the F2-layer peak height hmF2, respectively. Using an approach of discrete wavelet decomposition arithmetic, we have got the long-term components in the variations of the iono spheric parameters. It does exist nearly linear long-term decreasing trends of above ionospheric parameters from 1947 to 1990, then a nearly linear increase from 1990 to 2001. The decreases are approximately by 0. 35MHz, 0. 4MHz, 2MHz,20km, respectively, for foE, foF1, foF2 and hmF2, but increase by 4km for h'E,from 1947 to 1990. Simultaneously, we find similar long-term trends in the variations of 10.7cm solar radio flux and in sunspot number. The long-term components of the ionospheric parameters have extremely high correlation with those of 10.7cm solar radio flux and sunspot number. This implies that solar activities are the control factor of the long-term trends of the ionosphere. We confirm above conclusions with results from the long-term data at Slough station, UK. 相似文献
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With long-term ionosonde records from 1947 to 2001 at Chong-qing, China, we show long-term trends of the ionospheric parameters, the critical frequencies of E-layer foE, F1-layer foF1 and F2-layer foF2, the E-layer height h'E, and the F2-layer peak height hmF2, respectively. Using an approach of discrete wavelet decomposition arithmetic, we have got the long-term components in the variations of the iono spheric parameters. It does exist nearly linear long-term decreasing trends of above ionospheric parameters from 1947 to 1990, then a nearly linear increase from 1990 to 2001. The decreases are approximately by 0. 35MHz, 0. 4MHz, 2MHz,20km, respectively, for foE, foF1, foF2 and hmF2, but increase by 4km for h'E,from 1947 to 1990. Simultaneously, we find similar long-term trends in the variations of 10.7cm solar radio flux and in sunspot number. The long-term components of the ionospheric parameters have extremely high correlation with those of 10.7cm solar radio flux and sunspot number. This implies that solar activities are the control factor of the long-term trends of the ionosphere. We confirm above conclusions with results from the long-term data at Slough station, UK. 相似文献
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针对上合期间太阳风湍涡不规则性对穿过日冕区无线电波所引发的太阳闪烁问题,基于弱闪烁理论提出一种幅度起伏、相位起伏和到达角起伏的预测模型.该模型充分考虑了上合期间通信链路的几何模型、日冕背景参数和太阳风湍涡谱模型.仿真结果指出,太阳风湍涡外尺度、湍涡谱指数对太阳闪烁有较大的影响.太阳闪烁对无线电波的影响随日径距离的增大而逐渐减小,且随无线电波工作频率的提高而减小.与实测数据的对比结果进一步表明,所提预测模型具有较高的精度,且其准确性随电波工作频率的增大而提高.因此,提出的太阳闪烁预测模型可对未来的深空探测活动提供参考依据. 相似文献
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射电精细结构是太阳爆发动态频谱图中一个重要的观测现象。为了达到更好提取精细结构轮廓,解读物理信息的目的。基于国家天文台怀柔观测站的2.6~3.8GHz频谱仪于2002年4月21日观测到的爆发现象,采用Levelset方法并加以改进,对原始图像进行轮廓提取,克服了以往此方法中存在遗漏检测的问题。此外对图像进行循环检测,取得了良好地检测结果。此后又对图像进行二值化提取,得到了二值化精细结构图像。最终统计出精细结构漂移率这一重要物理信息,为更好的理解太阳爆发机制提供了依据。 相似文献
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A. I. Efimov L. A. Lukanina L. N. Samoznaev I. V. Chashei M. K. Bird 《Journal of Communications Technology and Electronics》2010,55(11):1253-1259
Frequency fluctuation data of monochromatic radio waves propagating through the circumsolar plasma in 1975–2002 are systematized
and analyzed. The radial dependences of the intensity of the frequency fluctuations are obtained for the decimeter radio waves
in the circumsolar plasma from the results of radio sounding using the Ulysses and Galileo spacecrafts. It is demonstrated
that the radial profile of the rms frequency fluctuations can be approximated by a power-law function whose exponent is determined
by the intensity of the plasma inhomogeneities, the velocity of solar wind, the spectral index of the spatial spectrum of
the plasma fluctuations, and the outer scale of turbulence. It is also shown that three different frequency fluctuation regimes
are found in the solar wind acceleration region and in the inner and outer regions of the stable solar wind. 相似文献