Asymmetrical Y-shaped and Y-ring-shaped frequency selective fabrics(FSFs) were proposed in this paper. They were prepared by computer engraving technology and tested in the anechoic chamber by using the free-space met...Asymmetrical Y-shaped and Y-ring-shaped frequency selective fabrics(FSFs) were proposed in this paper. They were prepared by computer engraving technology and tested in the anechoic chamber by using the free-space method. The test results of representative samples show that the resonance frequencies and the resonance peak or valley values in two polarization modes are not completely identical but the differentials are small, indicating that the influences of polarization modes are not significant. The transmission coefficient curves of Y-shaped and Y-ring-shaped FSFs with various size parameters are obviously different. For instance, as the unit size D increases by 4.0 mm, the resonance frequencies of patch FSFs decrease by 1.92 GHz and the resonance valleys increase by 12.32 dB. Different size parameters have dissimilar effects on the transmission characteristics and the corresponding influence laws should be analyzed concretely. The work could provide reference for the structural design and characteristics analysis of other FSFs.展开更多
CaN nanorods are successfully fabricated by adjusting the flow rate ratio of hydrogen （H2）/nitrogen （N2） and growth temperature of the selective area growth （SAG） method with metal organic chemical vapor deposit...CaN nanorods are successfully fabricated by adjusting the flow rate ratio of hydrogen （H2）/nitrogen （N2） and growth temperature of the selective area growth （SAG） method with metal organic chemical vapor deposition （MOCVD）. The SAG template is obtained by nanospherical-lens photolithography. It is found that increasing the flow rate of 1-12 will change the CaN crystal shape from pyramid to vertical rod, while increasing the growth temperature will reduce the diameters of GaN rods to nanometer scale. Finally the CaN nanorods with smooth lateral surface and relatively good quality are obtained under the condition that the H2：N2 ratio is 1：1 and the growth temperature is 1030℃. The good crystal quality and orientation of GaN nanorods are confirmed by high resolution transmission electron microscopy. The cathodoluminescence spectrum suggests that the crystal and optical quality is also improved with increasing the temperature.展开更多
基金Natural Science Foundation of Fujian Province,China (Nos.2019J01740 and 2021J05187)Education and Scientific Research Foundation for Middle-Aged and Young Scientist of Fujian Province,China (Nos.JT180377 and JAT190527)+2 种基金Quanzhou City Science&Technology Program of China (Nos.2018K002 and 2020C039R)Startup Foundation for Doctors of Quanzhou Normal University,China (Nos.H18024 and H18028)Innovation and Entrepreneurship Training Project for College Students,China (Nos.S201910399036 and 202010399113)。
文摘Asymmetrical Y-shaped and Y-ring-shaped frequency selective fabrics(FSFs) were proposed in this paper. They were prepared by computer engraving technology and tested in the anechoic chamber by using the free-space method. The test results of representative samples show that the resonance frequencies and the resonance peak or valley values in two polarization modes are not completely identical but the differentials are small, indicating that the influences of polarization modes are not significant. The transmission coefficient curves of Y-shaped and Y-ring-shaped FSFs with various size parameters are obviously different. For instance, as the unit size D increases by 4.0 mm, the resonance frequencies of patch FSFs decrease by 1.92 GHz and the resonance valleys increase by 12.32 dB. Different size parameters have dissimilar effects on the transmission characteristics and the corresponding influence laws should be analyzed concretely. The work could provide reference for the structural design and characteristics analysis of other FSFs.
基金Supported by the Key Program of the National Natural Science Foundation of China under Grant No 61334009the National High Technology Research and Development Program of China under Grant No 2014AA032604
文摘CaN nanorods are successfully fabricated by adjusting the flow rate ratio of hydrogen （H2）/nitrogen （N2） and growth temperature of the selective area growth （SAG） method with metal organic chemical vapor deposition （MOCVD）. The SAG template is obtained by nanospherical-lens photolithography. It is found that increasing the flow rate of 1-12 will change the CaN crystal shape from pyramid to vertical rod, while increasing the growth temperature will reduce the diameters of GaN rods to nanometer scale. Finally the CaN nanorods with smooth lateral surface and relatively good quality are obtained under the condition that the H2：N2 ratio is 1：1 and the growth temperature is 1030℃. The good crystal quality and orientation of GaN nanorods are confirmed by high resolution transmission electron microscopy. The cathodoluminescence spectrum suggests that the crystal and optical quality is also improved with increasing the temperature.
