Microwaves are often used in communication engineering,including in microwave relays as well as mul-tichannel,mobile,and satellite communications.To meet the demand for a“small,light,thin,and precise”modern electron...Microwaves are often used in communication engineering,including in microwave relays as well as mul-tichannel,mobile,and satellite communications.To meet the demand for a“small,light,thin,and precise”modern electronic machine,developing highly tunable microwave materials to manufacture miniaturized microwave devices has become a top priority.Ferroelectric materials are excellent microwave materi-als,showing outstanding dielectric properties and tunability.Introducing low dielectric loss oxides in the construction of vertical self-assembly nanocomposites(VSNs)effectively improves their tunability and reduces dielectric loss.However,the optimal doping content of simple VSN films limits further improve-ment of tunability.Herein,we propose a strategy-gradient VSN to achieve combined improvement in tunability and dielectric constant by designing a sputtering and pulsed laser co-deposition.The resulting VSN composite film has a dielectric constant of 428.08,a dielectric loss of 0.0212,and a tunability of 78.69%.Our results contribute to the development of filters and have broad application prospects in the microwave industry.展开更多
We analyze the cross section of e + e-→τ + μ-within the frameworks of SM and its Z extension.The theoretical prediction of the SM on the total cross section is suppressed by the tiny neutrino masses.On the other ha...We analyze the cross section of e + e-→τ + μ-within the frameworks of SM and its Z extension.The theoretical prediction of the SM on the total cross section is suppressed by the tiny neutrino masses.On the other hand,the contributions from Z to the cross section are enhanced drastically because of the tree level FCNC couplings among Z and leptons.展开更多
The production of Bc and B＊ mesons at a Z-factory （an e＋e- collider operating at energies around the Z pole） is calculated up to the next-to-leading order （NLO） QCD accuracy. The results show that the dependence...The production of Bc and B＊ mesons at a Z-factory （an e＋e- collider operating at energies around the Z pole） is calculated up to the next-to-leading order （NLO） QCD accuracy. The results show that the dependence of the total cross sections on the renormalization scale/1 is suppressed by the corrections, and the NLO corrections enhance the total cross sections of B,. by 52% and of Bc＊ by 33% when the renormalization scale is taken at μ = 2mb. To observe the various behaviors of the production of the mesons Bc and Bc＊, such as the differential cross section vs. the out-going angle, the forward-backward asymmetry, and the distribution vs. the energy fraction z up to NLO QCD accuracy as well as the relevant K-factor （NLO to LO） for the production, are calculated, and it is pointed out that some of the observables obtained in the present work may be used as a specific precision test of the standard model.展开更多
基金supported by the NSFC(No.11374086)and the NSF of Hebei Province(No.E2014201188)the Post-graduate Innovation Fund Project of Hebei University(No.HBU2022bs009)the Project of Distinguished Young of Hebei Province(No.A2018201231).
文摘Microwaves are often used in communication engineering,including in microwave relays as well as mul-tichannel,mobile,and satellite communications.To meet the demand for a“small,light,thin,and precise”modern electronic machine,developing highly tunable microwave materials to manufacture miniaturized microwave devices has become a top priority.Ferroelectric materials are excellent microwave materi-als,showing outstanding dielectric properties and tunability.Introducing low dielectric loss oxides in the construction of vertical self-assembly nanocomposites(VSNs)effectively improves their tunability and reduces dielectric loss.However,the optimal doping content of simple VSN films limits further improve-ment of tunability.Herein,we propose a strategy-gradient VSN to achieve combined improvement in tunability and dielectric constant by designing a sputtering and pulsed laser co-deposition.The resulting VSN composite film has a dielectric constant of 428.08,a dielectric loss of 0.0212,and a tunability of 78.69%.Our results contribute to the development of filters and have broad application prospects in the microwave industry.
基金supported by the National Natural Science Foundation of China (Grant Nos.10975027,10675027,and 10775073)
文摘We analyze the cross section of e + e-→τ + μ-within the frameworks of SM and its Z extension.The theoretical prediction of the SM on the total cross section is suppressed by the tiny neutrino masses.On the other hand,the contributions from Z to the cross section are enhanced drastically because of the tree level FCNC couplings among Z and leptons.
基金supported by the National Natural Science Foundation of China(Grant Nos.11275243,11275036,11447601,11535002,and 11675239)
文摘The production of Bc and B＊ mesons at a Z-factory （an e＋e- collider operating at energies around the Z pole） is calculated up to the next-to-leading order （NLO） QCD accuracy. The results show that the dependence of the total cross sections on the renormalization scale/1 is suppressed by the corrections, and the NLO corrections enhance the total cross sections of B,. by 52% and of Bc＊ by 33% when the renormalization scale is taken at μ = 2mb. To observe the various behaviors of the production of the mesons Bc and Bc＊, such as the differential cross section vs. the out-going angle, the forward-backward asymmetry, and the distribution vs. the energy fraction z up to NLO QCD accuracy as well as the relevant K-factor （NLO to LO） for the production, are calculated, and it is pointed out that some of the observables obtained in the present work may be used as a specific precision test of the standard model.
