Abstract: The present invention relates to a high-frequency radiation unit and a multi-frequency base station antenna. The high-frequency radiation unit comprises a radiator, a vibrator base, a first feeding member and a second feeding member. The distance between a first vertical section and a center line is greater than the distance between a first balun and the center line, and the distance between a second vertical section and the center line is greater than the distance between a second balun and the center line, that is, the first vertical section is disposed on one side of the first balun away from the center line, and the second vertical section is disposed on one side of the second balun away from the center line.

Abstract: The present disclosure relates to a domain decomposition method and system for electromagnetic simulation. The method includes: dividing an antenna structure model into multiple subdomains, where each of the subdomains corresponds to a structure in one to-be-simulated array antenna; subdividing each of the subdomains by a tetrahedral network to obtain multiple tetrahedrons; obtaining a vector basis function of each edge of each of the tetrahedrons according to vertex positions and lengths of the edges of the tetrahedron; and calculating an electric field value and a magnetic field value of any point in a tetrahedron to which each of the edges belongs using a vector basis function corresponding to the edge and a double curl electric field wave equation of a subdomain to which the edge belongs.

Abstract: A flexible gastight material for a landfill site includes a component A and a component B, the component A including: at least one of polypropylene glycol with a molecular weight of 600-4000, polytetrahydrofuran diol with a molecular weight of 1000-3000, polycaprolactone diol with a molecular weight of 1000-3000, and polycarbonate diol with a molecular weight of 1000-3000; and at least one of 2,4?-diphenylmethane diisocyanate, 4,4?-diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate. The flexible gastight material for the landfill site provided in the present application has a micro-closed-cell foam structure. The closed-cell elastic structure of the flexible gastight material may block the volatilization of toxic and harmful odors, and may cut off the diffusion path of the odors by combining with gas treatment systems at the landfill site. The flexible gastight material has excellent water blocking and gas sealing performance.

Abstract: A method for diagnosing an internal loss mechanism of a solar cell is provided. The solar cell includes an anode and a cathode. An electron transport layer, an active layer and a hole transport layer are arranged in sequence from top to bottom between the cathode and the anode. The solar cell is modeled through a solar cell multi-physics simulation platform. Current density-voltage (JV) curves respectively of type A, type B, type C and type D are simulated by regulating a bulk defect and a surface defect of the active layer and a voltage scan rate. The solar cell is subjected to forward voltage scan and reverse voltage scan to obtain forward and reverse JV curves. According to the forward and reverse JV curves, whether the JV curve type of the solar cell is the type A, the type B, the type C or the type D is determined.

Abstract: The present application relates to a pyrimidopyran compound, and specifically discloses a compound as represented by formula (III), and a pharmaceutically acceptable salt thereof.

Abstract: An ultra-wideband electromagnetic band gap (EBG) structure includes multiple EBG units in an array. Each EBG unit includes a power plane, a dielectric substrate and a ground plane from top to bottom. The power plane includes a patch, a coupled complementary split ring resonator (C-CSRR) and a plurality of semi-improved Z-bridge structures. Each edge of the patch is provided with a semi-improved Z-bridge structure. The C-CSRR is provided within a ring formed by the semi-improved Z-bridge structures. The Z-bridge structure includes a first horizontal branch, a first vertical branch, a second horizontal branch and a second vertical branch connected in sequence. The second vertical branch is connected to the patch. First horizontal branches of adjacent EBG units are connected to each other. A circuit board including the aforementioned EBG structure is also provided.

Abstract: A tilt rotor-based linear multi-rotor unmanned aerial vehicle (UAV) structure for crop protection and a control method thereof are provided. The tilt rotor-based linear multi-rotor UAV structure for crop protection includes main lift power structures, tilt power structures, and a main frame structure, where the main frame structure is located in a middle; the main lift power structures are distributed at left and right ends of the main frame structure; and the tilt power structures are symmetrically distributed between the main frame structure and the main lift power structures. A vector power structure is adopted to ensure flexible attitude changes and smoother and more accurate UAV operations, and improve the operation efficiency. Meanwhile, the tilt rotor-based linear multi-rotor UAV structure is adapted to the complex working environment in China's ever-changing terrains.

Abstract: Disclosed are a broadband millimeter-wave circularly polarized antenna element, a single-mode array, and a dual-mode array, relating to the technical field of circularly polarized antennas. A microstrip feeder is arranged on a lower surface of a second dielectric substrate of the antenna element. A coupling slot is etched on a metal ground layer, two metallized vias are formed on a first dielectric substrate, and a metal strip is tiled on an upper surface of the first dielectric substrate. Two L-shaped parasitic patches are also tiled on the first dielectric substrate. The two L-shaped parasitic patches are located on both sides of the metal strip, and the two L-shaped parasitic patches are rotationally symmetric about a center point of the upper surface of the first dielectric substrate. According to the present disclosure, a 3-dB axial ratio bandwidth of the antenna element is improved by using L-shaped parasitic patches.

Abstract: A tilt rotor-based linear multi-rotor unmanned aerial vehicle (UAV) structure for crop protection and a control method thereof are provided. The tilt rotor-based linear multi-rotor UAV structure for crop protection includes main lift power structures, tilt power structures, and a main frame structure, where the main frame structure is located in a middle; the main lift power structures are distributed at left and right ends of the main frame structure; and the tilt power structures are symmetrically distributed between the main frame structure and the main lift power structures. A vector power structure is adopted to ensure flexible attitude changes and smoother and more accurate UAV operations, and improve the operation efficiency. Meanwhile, the tilt rotor-based linear multi-rotor UAV structure is adapted to the complex working environment in China's ever-changing terrains.

Abstract: Bidirectional circularly polarized antenna element and bidirectional circularly polarized array antenna are provided, and comprising a dielectric substrate, a feeder, a radiation patch, a first plane, a second plane, a first coupling assembly and a second coupling assembly which are embedded in the surface of the dielectric substrate. The first plane and the second plane of the antenna element are kept at different heights, and compared with the solution that two planes at the same height can only generate linear polarization radiation in the prior art, the circular polarization radiation can be generated, which solves the problem of linear polarization mismatch. Furthermore, two coupling assemblies are introduced into two sides of the radiation patch to enable the coupling effect with the radiation patch, such that the frequency bandwidth of the circularly polarized antenna can be greatly improved without increasing the size of the antenna.

Abstract: Preparation and application of a series of polypeptides, and specifically disclosed is a polypeptide having a sequence as shown in formula (II). YAibEGT FTSDY SIAibLD KIAQK AFVKW LIAGG PSSGA PPPS0??(II).

Abstract: A silicon-on-insulator metal-oxide-semiconductor field-effect transistor (SOI MOSFET) structure is provided, including a substrate layer; a buried oxide layer which is arranged on an upper surface of the substrate layer and is made of SiO2; an active zone which is arranged on an upper surface of the buried oxide layer; a source electrode and a drain electrode which are arranged on an upper surface of the active zone; a gate dielectric layer which is arranged between the source electrode and the drain electrode; a gate electrode which is provided in the gate dielectric layer; and a heat conduction column which penetrates through the buried oxide layer, and its top wall is in contact with the active zone. The heat conduction column dissipates heat in the active zone, resulting in a lattice temperature of the active zone will not increase extremely and avoiding a decrease of a current of the drain electrode.

Abstract: Provided are a crystal form of a compound represented by formula (I) and a preparation method therefor.

Abstract: A silicon-on-insulator metal-oxide-semiconductor field-effect transistor (SOI MOSFET) structure is provided, including a substrate layer; a buried oxide layer which is arranged on an upper surface of the substrate layer and is made of SiO2; an active zone which is arranged on an upper surface of the buried oxide layer; a source electrode and a drain electrode which are arranged on an upper surface of the active zone; a gate dielectric layer which is arranged between the source electrode and the drain electrode; a gate electrode which is provided in the gate dielectric layer; and a heat conduction column which penetrates through the buried oxide layer, and its top wall is in contact with the active zone. The heat conduction column dissipates heat in the active zone, resulting in a lattice temperature of the active zone will not increase extremely and avoiding a decrease of a current of the drain electrode.

Abstract: Provided are pyrimidine aromatic ring compounds. Specifically provided is a compound as represented by formula (II) or a pharmaceutically acceptable salt thereof.

Abstract: The present invention relates to a class of TrkA inhibitors and an application thereof in the preparation of a drug for the treatment of diseases associated with TrkA. The present invention specifically discloses compounds represented by formula (I) and formula (II), tautomer thereof or pharmaceutically acceptable salts thereof.

Abstract: For the problem of difficult roof anchor withdrawal at the end of a working face, a static crushing directional anchor withdrawal method at the end of a large-mining-height working face is provided. The method includes the following steps: designing key parameters of boreholes for static crushing, including a borehole position, a spacing between boreholes, a borehole depth, and a borehole diameter at the end of a working face; then determining parameters of a static crushing agent grouting technology device for the construction of a static crushing process; and carrying out an anchor withdrawal operation at the end.

Abstract: An amorphous form of dezocine analogue hydrochloride is represented by formula (II). An X-ray powder diffraction spectrum of the amorphous form is shown in FIG. 1.

Abstract: A three-dimensional structured multi-level interlocking structure and a preparation method thereof, the multi-level interlocking structure comprises: a first interlocking structure comprising a first bonding component, first bonding troughs and first macrostmctures alternately positioned on the surface of the first bonding component, and a second interlocking structure comprising a second bonding component, second bonding troughs and second macrostmctures alternately positioned on the surface of the second bonding component, the first macrostructures are aligned with the second bonding trough, and the second macrostmctures are aligned with the first bonding trough; and the first macrostructure has a first end away from the first bonding component and the second macrostructure has a first end away from the second bonding component, the first ends of the first macrostructure and the second macrostructure comprise a top plane, the first end of the first macrostructure extends past the top plane of the second mac