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合成孔径雷达(Synthetic aperture radar,SAR)自动目标识别(Automatic target recognition,ATR)是现代战场情报侦察、精确打击的重要支撑技术。为提升SAR ATR整体性能,提出基于二维投影特征多重集典型相关分析(Multiset canonical correlations analysis,MCCA)的方法。首先,采用若干二维随机投影矩阵对SAR图像进行特征提取,获得多层次特征描述。考虑到这些结果之间的相关性和可能存在的冗余及干扰,进一步通过MCCA对它们进行融合处理,获取单一特征矢量。基于稀疏表示分类器(Sparse representation-based classification,SRC)对融合特征矢量进行处理,判决目标类别。实验基于MSTAR数据集开展,对方法性能进行检验确认,结果能够验证其有效性。 相似文献
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推动公民科学素质基准的制定对于提升我国公民科学素质水平、指导科普活动的开展、建设创新型国家具有重要的意义.目前学界针对美国科学素质基准的研究较多,对日本科学素质基准的研究较少.以日本公民科学素质基准建设的重要成果——《综合报告书》为研究对象,主要运用文本分析、归纳研究等方法,并以日本学者的相关研究成果为基础展开讨论.结果表明,日本公民科学素质基准框架构筑中包含了植根于本国文化传统、注重多领域知识融合、重视基准的长效落实等优秀理念.最终为我国目前公民科学素质建设提出了针对性的建议. 相似文献
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维多利亚时代,与科学有关的期刊发展迅速,其中大名鼎鼎的《自然》(Nature)就在这一时期创刊。本文通过资料分析发现,《自然》虽然取得了成功,也是当时唯一一份维持到现在的世界级科学期刊,但是,另外一些期刊也依然值得纪念,如波达创办并经营的《知识》。这一期刊与《自然》曾经相伴相争,共同走过了一段岁月,最终消亡。不过本文认为,这一期刊从某种意义上更加具有科普的气息,而且更加为公众所喜爱。 相似文献
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茅以升"专业科学"思想是其工程教育思想和科普理念的延续,受到了恩格斯自然辩证法与《实践论》、新中国发展科学理念的影响."专业科学"强调在专业基础上理论化,阐述了现场技术创造与科学创造的深层次关系,是科学家的专业思考与新中国科学发展实践紧密结合的产物,其中关于科研与生产关系、科研与科普关系、科学发展道路等思想对认识新时代科学发展问题仍具有启发价值. 相似文献
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The superconducting quantum interference device(SQUID) amplifier is widely used in the field of weak signal detection for its low input impedance, low noise, and low power consumption. In this paper, the SQUIDs with identical junctions and the series SQUIDs with different junctions were successfully fabricated. The Nb/Al-AlO_x/Nb trilayer and input Nb coils were prepared by asputtering equipment. The SQUID devices were prepared by a sputtering and the lift-off method.Investigations by AFM, OM and SEM revealed the morphology and roughness of the Nb films and Nb/Al-AlO_x/Nb trilayer.In addition, the current–voltage characteristics of the SQUID devices with identical junction and different junction areas were measured at 2.5 K in the He~3 refrigerator. The results show that the SQUID modulation depth is obviously affected by the junction area. The modulation depth obviously increases with the increase of the junction area in a certain range. It is found that the series SQUID with identical junction area has a transimpedance gain of 58 ? approximately. 相似文献
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Low temperature testing and neutron irradiation of a swept charge device on board the HXMT satellite
王于仨 陈勇 徐玉朋 杨彦佶 崔苇苇 李茂顺 刘晓艳 王娟 韩大炜 陈田祥 李承奎 霍嘉 李正伟 李炜 胡渭 张艺 陆波 朱玥 刘琰 吴帝 孙庆荣 张子良 《中国物理 C》2012,36(10):991-995
We present the low temperature testing of an SCD detector, investigating its performance such as readout noise, energy resolution at 5.9 keV and dark current. The SCD's performance is closely related to temperature, and the temperature range of -80 ℃ to -50 ℃ is the best choice, where the FWHM at 5.9 keV is about 130 eV. The influence of the neutron irradiation from an electrostatic accelerator with fluence up to 1×109 cm-2 has been examined. We find the SCD is not vulnerable to neutron irradiation. The detailed operations of the SCD and the test results of low temperature are reported, and the results of neutron irradiation are discussed. 相似文献
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