摘要：Nonprecious metal-based oxygen reduction reaction(ORR)electrocatalysts with high efficiency in both alkaline and acidic media are being intensively studied for the purpose of replacing expensive Pt-based catalysts;however,it is still a challenge to achieve superior ORR performances,especially in acidic ***,by pyrolysis of mixed precursors of diammonium phosphate,melamine and hemin,we prepared a nanocomposite catalyst(denoted as FeP@PGL)composed of nitrogen-doped carbon nanosheets with embedded FeP nanoparticles(NPs),which were encapsulated by in-situ formed phosphorus-doped graphene *** is found that phosphorous was preferentially doped in the coating layers on FeP NPs,instead of in the carbon *** FeP@PGL catalyst exhibited excellent ORR performance,with the onset and half-wave potential up to 1.01 and 0.90 V *** reversible hydrogen electrode(RHE)in alkaline media,and0.95 and 0.81 V *** in acidic media,*** thorough microscopy and spectroscopy characterizations,the interfacial charge transfer between the encapsulated FeP NPs and P-doped graphene layers was identified,and the local work function of the catalyst surface was also reduced by the interfacial *** interfacial synergy between the encapsulated FeP and phosphorus-doped graphene layers was essential to enhance the ORR *** study not only demonstrates the promising ORR properties of the encapsulated-FeP-based nanocomposite catalyst,but also provides direct evidence of the interfacial charge transfer effect and its role in ORR process.

摘要：超可靠低时延通信是5G及未来6G无线通信系统的重要组成部分.针对该类通信场景,如何从MIMO传输的角度实现时延和可靠性的最佳折中,是近年来备受关注的一项研究课题.由于现有基于长包假设的经典MIMO传输体系难以满足系统对于时延和可靠性的严苛要求,亟需研究更具挑战性的有限块长MIMO传输理论和技术.本文围绕有限块长MIMO信息论、发射机以及接收机设计的已有研究工作进行全面总结,并重点介绍二维空时信道编码以及MIMO一体化接收机等新型技术,为显著提升超可靠低时延通信的性能提供指导.另外,本文简要介绍了作者所在课题组搭建的MIMO超可靠低时延试验验证平台,为后续相关理论与算法的验证奠定试验基础.

摘要：综合采用多种传感器、嵌入式系统、LoRa、计算机技术设计实现了果园物联网系统,满足一般的果园环境参数采集监测和智能灌溉,实现了果品品质改善功能,即在6—8月果熟期的夜间特定时间段弥撒16℃低温水雾,降低果园夜间的环境温度,减弱果树的呼吸作用,促进水果有机物积累和糖分转换,并在合作桃园进行了验证试验.试验表明:当日温度为37℃~28℃的情况下,将果园夜间温度降低到17℃,昼夜温差达20℃,降温效果显著.