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科学回眸50年,100年和150年前
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作者 郭凯声 赵辉 《科学(中文版)》 2003年第3期5-5,共1页
射电望远镜——“随着射电望远镜(radio telescope)的分辨率不断提高,用射电望远镜观测到的星空图也越来越清晰。现在科学家们已经能够清楚了解到,天空中恒星最密集的区域产生的无线电波最强烈。虽然我们尚未完全掌握无线电源的具体... 射电望远镜——“随着射电望远镜(radio telescope)的分辨率不断提高,用射电望远镜观测到的星空图也越来越清晰。现在科学家们已经能够清楚了解到,天空中恒星最密集的区域产生的无线电波最强烈。虽然我们尚未完全掌握无线电源的具体情况,但了解到的这种关系对天文学非常重要。 展开更多
关键词 射电望远镜 精神分裂症的心理疗法 无线电商业 工业发展 煤油灯 科学事业史
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Digital Dividend: The Path Towards Business and Marketing Development
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作者 George Mastorakis 《Chinese Business Review》 2011年第12期1131-1137,共7页
Wireless radio spectrum is an important resource that allows for increased business development, throtigh the provision of services using wireless networking infrastructures. Since radio spectrum is limited, an optima... Wireless radio spectrum is an important resource that allows for increased business development, throtigh the provision of services using wireless networking infrastructures. Since radio spectrum is limited, an optimal utilization of it is required, by adopting advanced spectrum management methods. The current transition from analogue to digital terrestrial television may act as a unique opportunity, in order to reallocate this valuable spectrum resource. After the transition, a part of the traditional analogue television spectrum bands will be completely released, allowing for the use of this spectrum by sophisticated wireless systems. Furthermore, digital terrestrial television interleaves spectrum bands in order to avoid possible interference between adjacent channels used by broadcasting stations, thus leaving spectrum holes exploited by novel wireless networks, namely unlicensed secondary systems. In this context, this article investigates business and marketing development issues, arising by utilizing released and interleaved television spectrum bands 展开更多
关键词 radio spectrum digital dividend business and marketing development
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