Since the evolving standardization of cellular V2X(C-V2X)technologies is continuously developed by 3GPP,research on new radio(NR-V2X)has been on schedule by academic and industries.Though millimeter wave(mm Wave)frequ...Since the evolving standardization of cellular V2X(C-V2X)technologies is continuously developed by 3GPP,research on new radio(NR-V2X)has been on schedule by academic and industries.Though millimeter wave(mm Wave)frequency band is supposed to provide large transmission bandwidth,yet the development of mm Wave band in NR-V2X is still in preliminary stage.In this article,a comprehensive discussion of mm Wave NR-V2X is given covering trends,standardization landscape,and enabling technologies,aiming at tackling the challenge of channel modeling,directional channel access,beamforming and blockage management.The vision of mm Wave NR-V2X is to fully support the development of automated driving,holographic control display and improved in-car infotainment for the future.展开更多
Nanometer micro-porous Nix Zn (1-x )Fe2O4power was synthesized by hydrotherm al method.This is first time to apply template to the synthesis.The structure,characteristics and cry stal appearance are studied further by...Nanometer micro-porous Nix Zn (1-x )Fe2O4power was synthesized by hydrotherm al method.This is first time to apply template to the synthesis.The structure,characteristics and cry stal appearance are studied further by XRD,DSC,TEM,etc.It is found that nanome ter micro-porous crystal is well-crystallized,well-degree of dispers ion and smaller than 100nm in diameter.More over,tri-ethylamine can be used to b e a ideal template in this synthesis,and the first time it is reported in our co untry.The synthesis mechanism is also preliminary discussed in this pap er.展开更多
With the pretreatment of pyrolysis, the uniform, smooth, dense and crack free Gd2O3∶Eu3+ films were obtained by sol-gel process without shielding atmosphere. Atomic force microscopy （AFM）, X-ray diffraction （XRD）...With the pretreatment of pyrolysis, the uniform, smooth, dense and crack free Gd2O3∶Eu3+ films were obtained by sol-gel process without shielding atmosphere. Atomic force microscopy （AFM）, X-ray diffraction （XRD）, Ellipsometry, transmission, photoluminescence and X-ray excited emission were applied to study to the surface morphology, structure, thickness and optical properties of the films. The results show that the films are made up of grains with cubic structure in average size about 22 nm. With 21 times reproducible spin coating and pyrolysis treatment, the thickness of the film could reach to 792 nm and the transmittance of the film in visible region is above 90%. Two peaks at 223 and 250 nm are found in excitation spectra, which correspond to host lattice （HL） excitation and charge transfer （CT） excitation, respectively. Meanwhile, the main peak relates to HL excitation which is contrary to that of Gd2O3∶Eu3+ powder. This phenomenon will be beneficial to radioluminescence. The emission spectra show that the main peak located at 611 nm could be excited either by UV or X-ray, which correspond to （（）7F2→（）5D0） transition in Eu3+ ions. The luminescence intensity at 10 ms is only 10-4 time of that at 10 μs, which means that the afterglow in Gd2O3∶Eu3+ films is insignificant for X-ray imaging.展开更多
基金supported by the National Key Research and Development Program of China(2020YFB1807900)the National Natural Science Foundation of China(61931005,62001051)。
文摘Since the evolving standardization of cellular V2X(C-V2X)technologies is continuously developed by 3GPP,research on new radio(NR-V2X)has been on schedule by academic and industries.Though millimeter wave(mm Wave)frequency band is supposed to provide large transmission bandwidth,yet the development of mm Wave band in NR-V2X is still in preliminary stage.In this article,a comprehensive discussion of mm Wave NR-V2X is given covering trends,standardization landscape,and enabling technologies,aiming at tackling the challenge of channel modeling,directional channel access,beamforming and blockage management.The vision of mm Wave NR-V2X is to fully support the development of automated driving,holographic control display and improved in-car infotainment for the future.
文摘Nanometer micro-porous Nix Zn (1-x )Fe2O4power was synthesized by hydrotherm al method.This is first time to apply template to the synthesis.The structure,characteristics and cry stal appearance are studied further by XRD,DSC,TEM,etc.It is found that nanome ter micro-porous crystal is well-crystallized,well-degree of dispers ion and smaller than 100nm in diameter.More over,tri-ethylamine can be used to b e a ideal template in this synthesis,and the first time it is reported in our co untry.The synthesis mechanism is also preliminary discussed in this pap er.
文摘With the pretreatment of pyrolysis, the uniform, smooth, dense and crack free Gd2O3∶Eu3+ films were obtained by sol-gel process without shielding atmosphere. Atomic force microscopy （AFM）, X-ray diffraction （XRD）, Ellipsometry, transmission, photoluminescence and X-ray excited emission were applied to study to the surface morphology, structure, thickness and optical properties of the films. The results show that the films are made up of grains with cubic structure in average size about 22 nm. With 21 times reproducible spin coating and pyrolysis treatment, the thickness of the film could reach to 792 nm and the transmittance of the film in visible region is above 90%. Two peaks at 223 and 250 nm are found in excitation spectra, which correspond to host lattice （HL） excitation and charge transfer （CT） excitation, respectively. Meanwhile, the main peak relates to HL excitation which is contrary to that of Gd2O3∶Eu3+ powder. This phenomenon will be beneficial to radioluminescence. The emission spectra show that the main peak located at 611 nm could be excited either by UV or X-ray, which correspond to （（）7F2→（）5D0） transition in Eu3+ ions. The luminescence intensity at 10 ms is only 10-4 time of that at 10 μs, which means that the afterglow in Gd2O3∶Eu3+ films is insignificant for X-ray imaging.
