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聚苯胺复合热电材料研究进展 被引量:5
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作者 尹四星 鹿文涛 +1 位作者 李小全 郭存悦 《高分子通报》 CAS CSCD 北大核心 2020年第12期58-62,共5页
热电材料是一种通过固体内部载流子迁移来实现热-电相互转换的新型功能材料。无机热电材料虽然拥有好的热电性能,但是难加工、造价高、有毒。而有机热电材料柔性高、易加工、资源丰富、成本低、绿色环保,已逐渐成为热电材料的研究重点... 热电材料是一种通过固体内部载流子迁移来实现热-电相互转换的新型功能材料。无机热电材料虽然拥有好的热电性能,但是难加工、造价高、有毒。而有机热电材料柔性高、易加工、资源丰富、成本低、绿色环保,已逐渐成为热电材料的研究重点。其中,聚苯胺(PANI)作为优良的导电聚合物,因其复合材料良好的热电性能逐渐引起人们的重视。本文介绍了聚苯胺复合热电材料近年来的研究进展,并对其未来的发展进行了展望。 展开更多
关键词 聚苯胺 复合材料 热电性能
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Quantitative spectrum occupancy evaluation in China: based on a large scale concurrent spectrum measurement
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作者 yin Liang yin si-xing +3 位作者 WANG Shuai ZHANG Er-qing HONG Wei-jun LI Shu-fang 《The Journal of China Universities of Posts and Telecommunications》 EI CSCD 2012年第3期122-128,共7页
Due to the usable frequency becomes more and more crowed, dynamic spectrum access (DSA) is a new hope to solve this problem. However, DSA in China requires a quantitative analysis of the current spectrum utilization... Due to the usable frequency becomes more and more crowed, dynamic spectrum access (DSA) is a new hope to solve this problem. However, DSA in China requires a quantitative analysis of the current spectrum utilization in frequency, temporal and spatial domains. In order to free the precious spectrum, spectrum regulation organizations must have a clear, detailed, up-to-date understanding of where, how and by whom spectrum is currently being used--such data is essential to sound policy decisions in the context of cognitive radio (CR). In this paper, a concurrent spectrum occupancy measurement in south China was conducted to evaluate the practical spectrum occupancy with a digital wideband receiver covering from 20 MHz to 3 GHz. We also propose systemic spectrum measurement methodology, matrix format data storage, duty cycle (DC) evaluation metric and data mining process which can be a guideline for other researchers when they conduct the similar experiments. Quantitative analysis and characterization of the 4 different measurement locations are evaluated to promote the popularization of CR application in China. And a uniform Beta distribution channel occupancy model is also validated using real-scene measurement data. The experimental results demonstrate that there is a significant scope for license-exemption use of the released spectrum using CR technology. 展开更多
关键词 cognitive radio spectrum measurement spectrum occupancy duty cycle Beta distribution
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