面向6G网络的技术发展,综述了世界各国和第三代合作伙伴计划(The 3rd Generation Partnership Project,3GPP)、电气和电子工程师协会(Institute of Electrical and Electronics Engineers,IEEE)、等国际组织在该领域的规划和已开展工作...面向6G网络的技术发展,综述了世界各国和第三代合作伙伴计划(The 3rd Generation Partnership Project,3GPP)、电气和电子工程师协会(Institute of Electrical and Electronics Engineers,IEEE)、等国际组织在该领域的规划和已开展工作情况,阐述了6G愿景和主要技术指标体系。针对无线接入这一核心技术环节,介绍了6G阶段新型波形、多址接入、信道编码以及无蜂窝大规模MIMO等技术研究和发展情况,重点叙述了全频谱、全覆盖、内生安全、全应用及人工智能等6G新范式的内涵、关键技术以及目前研究重点,最后对6G技术的未来发展进行了展望。展开更多
The relation between the tempering effects of sinterd SmCo^(5)alloy at 750℃and its intrinsic coercivity(i^(Hc))has been studied by the use of photoelectron energy spectrum.X-ray diffraction and high-voltage electron ...The relation between the tempering effects of sinterd SmCo^(5)alloy at 750℃and its intrinsic coercivity(i^(Hc))has been studied by the use of photoelectron energy spectrum.X-ray diffraction and high-voltage electron microscope.The result is that the cause of iHc dropping seriously for sintered SmCo_(5)alloy tempered at 750 t is not the eutectoid decomposition of SmCo_(5)and the increase of oxygen.In fact,iHcdropping is caused by that some defect-rich regions in Sm_(2)Co_(17)decomposed form SmC0_(5)from nucleation centers in reversed magnetization course.展开更多
The magnetic properties of (Nd_(0.9)Dy_(0.1))_(16)Co_(5)Fe_(70)Nb_(2)B_(7) permanent magnetic alloy prepared by powder metallurgy are:Br=1.08T,_(1)H_(C)=1620kA/m,(BH)_(max)=208kJ/m^(3).The behaviour of Nb in this allo...The magnetic properties of (Nd_(0.9)Dy_(0.1))_(16)Co_(5)Fe_(70)Nb_(2)B_(7) permanent magnetic alloy prepared by powder metallurgy are:Br=1.08T,_(1)H_(C)=1620kA/m,(BH)_(max)=208kJ/m^(3).The behaviour of Nb in this alloy was studied by joint methods of dynamic observation by high voltage electron microscope(HVEM)and Mossbauer effects.With Nb and Co substituting parts of Fe and adding a little Dy,practical magnetic alloy with excellent properties can be obtained.The thermal stability of it is 80 ℃ higher than that of ternary Nd-Fe-13 magnet.The study shows that adding Nb into Nd-Fe-B can make the intrinsic coercivity appear peak value at about Nb=2%(in mole fraction).Nb mainly enters into Nd-rich and B-rich phases,a little into Nd_(2)Fe_(14)B phase.展开更多
文摘面向6G网络的技术发展,综述了世界各国和第三代合作伙伴计划(The 3rd Generation Partnership Project,3GPP)、电气和电子工程师协会(Institute of Electrical and Electronics Engineers,IEEE)、等国际组织在该领域的规划和已开展工作情况,阐述了6G愿景和主要技术指标体系。针对无线接入这一核心技术环节,介绍了6G阶段新型波形、多址接入、信道编码以及无蜂窝大规模MIMO等技术研究和发展情况,重点叙述了全频谱、全覆盖、内生安全、全应用及人工智能等6G新范式的内涵、关键技术以及目前研究重点,最后对6G技术的未来发展进行了展望。
文摘The relation between the tempering effects of sinterd SmCo^(5)alloy at 750℃and its intrinsic coercivity(i^(Hc))has been studied by the use of photoelectron energy spectrum.X-ray diffraction and high-voltage electron microscope.The result is that the cause of iHc dropping seriously for sintered SmCo_(5)alloy tempered at 750 t is not the eutectoid decomposition of SmCo_(5)and the increase of oxygen.In fact,iHcdropping is caused by that some defect-rich regions in Sm_(2)Co_(17)decomposed form SmC0_(5)from nucleation centers in reversed magnetization course.
基金Supported by the State Key Laboratory of Magnetism,Chinese Academy of Sciences。
文摘The magnetic properties of (Nd_(0.9)Dy_(0.1))_(16)Co_(5)Fe_(70)Nb_(2)B_(7) permanent magnetic alloy prepared by powder metallurgy are:Br=1.08T,_(1)H_(C)=1620kA/m,(BH)_(max)=208kJ/m^(3).The behaviour of Nb in this alloy was studied by joint methods of dynamic observation by high voltage electron microscope(HVEM)and Mossbauer effects.With Nb and Co substituting parts of Fe and adding a little Dy,practical magnetic alloy with excellent properties can be obtained.The thermal stability of it is 80 ℃ higher than that of ternary Nd-Fe-13 magnet.The study shows that adding Nb into Nd-Fe-B can make the intrinsic coercivity appear peak value at about Nb=2%(in mole fraction).Nb mainly enters into Nd-rich and B-rich phases,a little into Nd_(2)Fe_(14)B phase.
