60results about How to "Few structural parameters" patented technology

The invention discloses a cross spiral frequency selective surface (FSS) structure with dual band characteristics and a construction method thereof. The structure consists of an upper dielectric layer, a lower dielectric layer and an intermediate cross spiral FSS structure layer. The construction method comprises the following six steps of: 1, establishing structure units of the cross spiral FSS structure layer with the thickness of zero by using computer simulation technology (CST) software; 2, periodically extending the structure units towards directions X and Y to obtain the integrated 6*6 cross spiral FSS structure layer; 3, establishing the dielectric layers of the cross spiral FSS structure, and embedding the cross spiral FSS structure layer into a dielectric substrate by using the CST software; 4, capturing the cross spiral FSS structure unit from the CST software for incident wave transmittance analysis, regulating parameters of the structure unit, changing the resonance frequency of a stop band, and replacing an original structure by using the regulated structure unit; 5, setting the parameters such as boundaries and the like of the constructed cross spiral FSS structure, and testing the bandwidth stability and frequency selectivity of the structure; and 6, machining and manufacturing the cross spiral FSS structure by adopting a double-sided copper-clad plate according to an optimal size determined by the step 4.

The invention discloses a substrate integrated waveguide technology-based high-gain circularly polarized antenna array and a manufacturing method of the antenna array. The broadband substrate integrated waveguide circularly polarized antenna array comprises an upper-layer radiation substrate and a lower-layer feed substrate, wherein the radiation substrate comprises a first antenna unit, a second antenna unit, a third antenna unit and a fourth antenna unit, and the first antenna unit, the second antenna unit, the third antenna unit and the fourth antenna unit are symmetrically arranged by taking the center of a circle as an axis; a radial substrate integrated waveguide power distributor which is divided into four parts is distributed on the feed substrate and is used for feeding the four antenna units. The high-gain circularly polarized antenna array disclosed by the invention has the advantages that the gain is high, the broadband is wide, the radiation characteristic is good, the design is simple, the machining is easy and the cost is low; compared with the current substrate integrated waveguide circularly polarized antenna, the antenna provided by the invention has the advantages that the gain is remarkably improved and the circularly polarized bandwidth is remarkably increased.

The present invention relates to a directional coupler feed low-profile cavity-backed circularly polarized antenna. The common cavity-backed circularly polarized antenna has complicated structure and large volume and can be planely integrated. In the invention two surfaces of the medium substrate is plated with metal layers, the upper metal layer is etched for the feed microstrip line, the branch line directional coupler with a microstrip form and the co-ground coplanar waveguide transmission line, a plurality of plated-through holes which are arranged to a square are arranged penetrating the upper metal layer, the medium substrate and the lower metal layer, the cavity is formed and the coplanar waveguide transmission line extends into the cavity. The lower metal layer is etched with two elongated radiating gap which are perpendicular to each other. Comparing with the existing cavity-backed circularly polarized antenna the invention adopts the 3dB directional coupler with 90 degree phase shift as the feed network, on the base of reserving the high grin character of the cavity-backed circularly polarized antenna, and the 3dB axial ratio bandwidth of the antenna is evidently increased. The whole structure can be manufactured with the PCB technique and the cost is low, the structure can be integrated with plane circuit seamlessly and the integrity is increased.

The invention is a frequency selective surface based on integrated waveguide technique, able to act as a frequency band multiplexer applied to multifrequency antennas of satellite, radar and other communication systems, act as radar antenna cover used for stealth technique, and be applied to manufacture multiplexed auxiliary surface of a multiplexed antenna in millimeter wave-infrared compound remote sensing technique and polarizers and beam separators in optical and quasi-optic systems. And it is carved with many corresponding double-layer periodic clearance channel units on double metallic sides of a dielectric substrate to compose an array of double-layer clearance channels, and periodically and at intervals arranges a series of metallized through holes around each double-layer periodic clearance channel unit on the substrate to form a substrate integrated waveguide cavity equivalent to a traditional metal cavity. As compared with ordinary pasted or slotted frequency selective surface, it has better pass band and better angle of incident wave and stability of polarity.

The present invention relates to a reduced size low profile cavity backed linearly polarized antenna. The performance of a single radiating element of a traditional linearly polarized antenna is low and the volume is large. In the present invention, a metal layer is plated on both sides of the dielectric substrate, and the upper metal layer is etched with a microstrip line for power feeding and a common ground coplanar waveguide transmission line, and the middle metal strip of the coplanar waveguide transmission line extends outwards as a microstrip line . Through the upper metal layer, the dielectric substrate and the lower metal layer, a plurality of metallized through holes arranged in a rectangle form a cavity, and the coplanar waveguide transmission line extends into the cavity. The lower metal layer is etched with a strip-shaped radiation slit with a wide side parallel to the wide side of the cavity and close to the wide side of the non-feeding end of the cavity in the region corresponding to the cavity. The invention adopts common PCB technology to produce, the production cost is significantly reduced, and the seamless integration with the microstrip circuit can be realized, and the integration degree of the system is improved. Compared with traditional cavity-backed antennas that require precise machining, the manufacturing speed is fast and the cost is low.

The invention relates to a cavity-backed circular polarization antenna for coplanar waveguide single-point feeding. The common cavity-backed circular polarization antenna has complicated structure, large volume, non-planar integration, as well as high cost. Two surfaces of a medium substrate of the invention are plated with metal layers, the upper metal layer is etched with a micro-strip line used for feeding, and a common ground and coplanar waveguide transmission line, and as the micro-strip line, the middle metal belt of the coplanar waveguide transmission line extends outwardly. The upper metal layer, the medium substrate, and the lower metal layer are opened with a plurality of metallized through holes arranged as a square, so as to form a cavity, and the coplanar waveguide transmission line dives into the cavity. The lower metal layer is etched with two mutually perpendicular long-shaped radiation slot in corresponding cavity area. Compared with the cavity-backed circular polarization antenna composed by prior metal cavity, the invention adopts common PCB process to manufacture, the manufacturing cost is low, and can realize seamless integration with the micro-strip circuit, thereby improving systemic integrated level.

The invention provides a multi-layer metamaterial surface structure for realizing multi-band frequency selective wave transmitting angles. The invention aims to solve the technical problem of difficulty in realizing multi-band regulation due to complex structures of existing active technologies in wave beam regulation. The multi-layer metamaterial surface structure is composed of a plurality of metamaterial surface units (1) which are distributed periodically; each metamaterial surface unit (1) includes N layers of dielectric substrates (2), where N is smaller than or equal to 5; each layer of dielectric substrate is printed with a metal patch (3); a double-opening annular slot (4) which is asymmetric in a vertical direction is formed in the metal patch (3) through etching; and the metal patches on the odd-number layers of dielectric substrates are arranged in a manner that the metal patches on the odd-number layers of dielectric substrates are rotated by 180 degrees relative to the metal patches on the even-number layers of dielectric substrates, so that coupling can be generated in the multi-layer metamaterial surface structure; and N-1 wave transmitting frequency bands are increased in low-frequency bands, so that electromagnetic waves can be subjected to frequency selective wave transmitting angular transmission in a plurality of frequency bands. The multi-layer metamaterial surface structure of the invention has the advantages of simple structure, convenient processing and easiness in maintenance, and can be used for the design of a multi-functional radome.

The invention provides a single-layer meta-material surface structure capable of realizing angle-selective filtering through filtering frequency change and mainly solves a problem of inconvenient electromagnetic wave filtering angle adjustment in the prior art. A single-layer meta-material surface comprises multiple single-layer meta-surface slit units (2) arranged in a periodic mode, each single-layer meta-surface slit unit comprises a medium substrate (21) and a metal paster (22), the medium substrate (21) is prepared by employing a square organic high-molecular polymer substrate with thickness of 0.5-0.8mm and the relative dielectric constant of 2.65-4.4, the metal paster (22) is printed on the medium substrate (21), an annular slit which is vertically etched, is asymmetric and has double openings is etched on the metal paster (22), and the metal paster (22) is used for realizing angle-selective filtering under a single frequency band to make an electromagnetic wave filtering angle generate offset along with change of meta-surface filtering frequency. The surface structure is advantaged in that the structure is simple, processing is convenient, and the surface structure can be applied to design of a multi-function antenna cover.

The invention relates to a lowly-outlined cavity-backed circularly polarized antenna based on the disturbance of plated-through hole. The existing cavity-backed circularly polarized antenna can not be planar integrated has a complex structure, a large size, and a high cost. In the invention, a metal layer is plated at two faces of a dielectric substrate; an upper metal layer is etched with a micro-strip line used for feeding and a coplanar waveguide transmission line; a middle metal strip of the coplanar waveguide transmission line extends outwards as a micro-strip line. A plurality of plated-through holes are installed by penetrating the upper metal layer, the dielectric substrate and a lower metal layer forming a round cavity into which the coplanar waveguide transmission line extends. Two strips of vertical rectangular slots are etched at the region on the lower metal layer of the corresponding cavity. Two perturbation plated-through holes are installed by penetrating the whole dielectric substrate at the two ends of the central line of one of the two slots. Compared with the existing cavity-backed circularly polarized antenna formed by the metal cavity, the cavity adopted by the invention is manufactured by the common PCB technology with a low manufacturing cost, and the invention can be seamlessly integrated with a micro-strip circuit, thus increasing the integrity of the system.

The invention discloses an electromagnetic band gap structure for optimizing a power distribution network of a PCB (printed circuit board), and the electromagnetic band gap structure is of a periodic structure. The shape of a periodic unit is formed by four large-size narrow-bridge-shaped connecting metal branches, eight small-size narrow-bridge-shaped connecting metal branches with same shapes, and square metal patches. All the periodic units are connected by utilizing the narrow-bridge-shaped connecting metal branches of all the edges. A construction method comprises the following seven main steps: (1) establishing a periodic structure unit layer of a zero-thickness composite coplanar EBG (Electromagnetic Band Gap) layer; (2) establishing a medium layer of the periodic structure units of the composite coplanar EBG layer; (3) establishing a dispersion diagram simulation model of the composite coplanar EBG periodic structure units; (4) carrying out periodic prolongation on the periodic structure units of the composite coplanar EBG layer obtained by the step (1) along the X and Y directions to obtain the composite coplanar EBG layer; (5) establishing a medium layer of an EGB structure and embedding the composite coplanar EBG structure layer into a substrate of a medium; (6) adding a simulation port to calculate an S parameter of the EBG structure; and (7) practically plating and testing the transmission characteristic of the composite coplanar EBG structure.

The invention relates to a high gain integrated antenna based on a high order cavity resonant mode. A backed cavity of the traditional antenna consists of a smooth metal cavity, and has a large volume and high processing cost. The high gain integrated antenna based on the high order cavity resonant mode comprises a dielectric substrate, an upper metal layer which is coated on the upper surface of the dielectric substrate, and a lower metal layer which is coated on the lower surface of the dielectric substrate. A plurality of electric interconnection units which pass through the upper metal layer, the dielectric substrate and the lower metal layer are arranged in sequence to form an electric interconnection array; an area which is surrounded by the upper metal layer, the lower metal layer and the electric interconnection array forms a cavity body, and a feed unit stretches into the cavity body; the plurality of electric interconnection units which pass through the upper metal layer, the dielectric substrate and the lower metal layer inside the cavity body form a plurality of tuning electric interconnection groups; and a plurality of parallel radiating gaps are formed on the upper metal layer inside the cavity body. The volume of the cavity backed antenna is greatly reduced; manufacturing cost is reduced remarkably; and seamless integration between the high gain integrated antenna based on the high order cavity resonant mode and a planar circuit can be realized.

The invention discloses a common mode filter based on a C type coupling defected ground structure. A coupled microstrip line used for transferring high-speed differential signals is manufactured on the top surface of a double-layer printed circuit board. The bottom surface of the circuit board is coated with copper to be used as a ground player. Two C type grooves are symmetrically etched on a ground plane right under the coupled microstrip line; namely, the grooves are of a defected ground structure. Directions of openings of the two C type grooves are opposite. The common mode filter based on the C type coupling defected ground structure is simple in design, few in structure parameters and small in effective electricity size.

The invention relates to a polarized antenna with wave guiding cavity-backed lines integrated on a rectangular substrate. The traditional polarized antenna has the disadvantages of low performance of single radiation unit, large bulk, complex structure and high manufacturing cost. The dielectric substrate of the invention is plated with metallic layers on two sides; the upper metallic layer is etched with a microstrip line for feeding and a plurality of coplanar wave guiding transmission lines; the coplanar wave guiding transmission lines are grounded coplanar wave guiding structure, wherein, the metallic strip in the middle is extended outwards to form the microstrip line. A plurality of metallized through holes, which are arrayed as a square, are penetrated through the upper metallic layer, the medium substrate and the lower metallic layer to form the cavity; the coplanar wave guiding transmission lines are extended into the cavity. An elongated radiation slit is etched on the lower metallic layer corresponding to the cavity. The invention has the advantages that: by adopting the general PCB technology, the production cost is notablely decreased and the invention can be integrated with the microstrip circuit without seam, the integrity of the system is improved; compared with the exact machining of the traditional cavity-backed antennas, the manufacture speed is high and the cost is low.

The invention relates to a rectification speed increasing tower used for a vertical axis wind turbine. The appearance of the rectification speed increasing tower is a layer or multiple layers of tower-shaped structures. The rectification speed increasing tower comprises a tower base (1), a fairing (2), a tower brim (3) and a tower top (4). The center of the tower is provided with a hollow columnar chamber, and the inside of the chamber is used for installing a vertical axis wind turbine set. The invention has the advantages that the speed increasing ratio of a speed increaser is reduced, the stress condition and the working condition of the vertical axis wind turbine are improved, the stability of the wind turbine is increased, the service life thereof is prolonged, the design difficulty of the wind turbine is lowered, the manufacture and transportation costs of the wind turbine are reduced, the environment is protected, the appearance is beautiful and the like.

The invention discloses a broadband substrate integrated waveguide circularly polarized antenna. The broadband substrate integrated waveguide circularly polarized antenna comprises a substrate, wherein the substrate is provided with an upper metal layer and a lower metal layer, a rhombus annular structure is etched on the upper metal layer, part of the annular structure is grounded to form short circuit, a metallization via hole running through the upper metal layer and the lower metal layer is formed in the annular structure, a plurality of metallization via holes running through the upper metal layer and the lower metal layer are formed on the periphery of a seam, the metallization via holes are sequentially arrayed to form a substrate integrated waveguide cavity body, the final substrate integrated waveguide cavity body is constructed by a rectangular area and a rhombus area, and a coaxial feed structure is arranged in a proper position of the rectangular area of the substrate integrated waveguide cavity body. The broadband substrate integrated waveguide circularly polarized antenna has the advantages of high gain, wide broadband, good radiation characteristic, simple design, easiness in machining, low cost and the like. Compared with an existing substrate integrated waveguide circularly polarized antenna, the gain of the antenna disclosed by the invention is obviously improved, and the circularly polarized bandwidth is remarkably improved.

The invention relates to a Gaussian even pulse high-current high-power broadband power line injection coupling network. The Gaussian even pulse high-current high-power broadband power line injection coupling network comprises a coupling unit and a decoupling unit; the coupling unit consists of an inductor, a capacitor and resistors, wherein the inductor and the capacitor are serially connected to increase series resonance points for expanding the frequency band for coupling a disturbance signal, and then are connected in series with the parallel two resistors, and are respectively added to the positive end and the negative end of a signal wire; the decoupling unit consists of an inductor, a capacitor and a transformer, the inductor and the capacitor of the decoupling unit constitute a low pass filter which is used for filtering a high-voltage noise signal out, and common mode rejection impedance is increased by serially connecting the low pass filter with the transformer under the condition of not increasing the insertion loss, so that the common mode noise in the signal wire is effectively rejected. A construction method of the Gaussian even pulse high-current high-power broadband power line injection coupling network comprises seven major steps. According to the Gaussian even pulse high-current high-power broadband power line injection coupling network and the construction method thereof, the design that traditional capacitive coupling is confined to certain bandwidth and small signal interference voltage coupling is overcome, the coupling frequency band range is expanded, and a relatively large common mode rejection impedance is provided.

The invention relates to a Gaussian even pulse high-current high-power broadband power wire injection coupling network. The Gaussian even pulse high-current high-power broadband power wire injection coupling network comprises a coupling unit and a decoupling unit; the coupling unit consists of an inductor, a capacitor and resistors, wherein the inductor and the capacitor are serially connected to increase series resonance points for expanding the frequency bandwidth for coupling a disturbance signal, and then an LC series resonance circuit is connected with the two resistors in series, and the interference signal is coupled into a power wire; the decoupling unit consists of an inductor and a capacitor which constitute a low pass filter used for filtering a high-voltage noise signal out, and a relatively large common mode rejection impedance is provided by setting a proper series inductance value under the condition that the insertion loss meets the requirements, so that the common mode noise of the power wire is effectively rejected. A construction method of the Gaussian even pulse high-current high-power broadband power line injection coupling network comprises eight major steps. The Gaussian even pulse high-current high-power broadband power line injection coupling network and the construction method thereof are simple and feasible, and the resistance can be adjusted according to the output impedance among different signal generators and the impedance among ground wires, and thus favorable coupling and decoupling performance can be realized.

The invention discloses a method for forecasting monthly runoff through secondary coupling under the condition of data shortage. The number of structure parameters of a coupling model is small, the structure of the coupling model is simple, the computational process is not limited by the requirement for the accuracy of calculated length, topographic data and meteorological data of hydrologic data, the realness of a model system in simulating a real hydrologic process is guaranteed by carrying out model coupling on a GRNN model and other physical models, and errors caused by the adoption of a large number of empirical formulas and setup parameters are effectively avoided; a traditional time series ARMA model is modified, and a seasonal ARMA model is applied to an extension technology for hydrologic data series; data coupling is carried out on the coupling model and monthly runoff data extended through the seasonal ARMA model to determine the structure and the parameters of the coupling model so that a coupled GRNN model acquired after secondary coupling can still guarantee the accuracy in simulating the runoff of a drainage basin of which hydrologic data are relatively insufficient, and therefore the method has low dependency on the historical hydrologic data and can effectively guarantee the practicality and applicability of the coupling model system.

The invention relates to a novel frequency selective surface with steep drop characteristic in both sides thereof. In the traditional frequency selective surface, the problems of low selectivity, poor performance stability and large volume exist. The novel frequency selective surface is characterized in that: metal layers are plated on both surfaces of a dielectric substrate; plated-through holes arranged in the patterns of large or small square groups run through the whole dielectric substrates to form a variety of high-frequency and low-frequency substrate integrated waveguide cavity groups; same square-shaped coupling gaps are etched for the upper and the lower metal layers in the adjacent high-frequency and low-frequency cavity. Compared with the general dual-band frequency selective surface formed by periodic patches or gaps of different sizes, since a cavity resonant mode is introduced into the new structure, the novel frequency selective surface with steep drop characteristic in both sides thereof realizes the steep drop characteristic of both sides of passbands and greatly improves the selection characteristic of the passbands, with excellent stability to the angles and the polarizability of incident waves.

The invention relates to a low profile cavity backed integrated antenna with a widened frequency band. A metal backed cavity of the traditional antenna has a large volume and high processing cost and is difficult to process. The low profile cavity backed integrated antenna with the widened frequency band comprises a dielectric substrate, an upper metal layer which is coated on the upper surface of the dielectric substrate, and a lower metal layer which is coated on the lower surface of the dielectric substrate. A plurality of electric interconnection units which pass through the upper metal layer, the dielectric substrate and the lower metal layer are arranged in sequence to form an electric interconnection array; an area which is surrounded by the upper metal layer, the lower metal layer and the electric interconnection array forms a cavity body; a feed unit stretches into the cavity body; and a linear type gap is formed on the metal layer inside the cavity body. The volume of the cavity backed antenna is reduced greatly, and an operation bandwidth of the low profile antenna of the type is reduced obviously at the same time; manufacturing cost is reduced remarkably; and seamless integration between the low profile cavity backed integrated antenna and a planar circuit can be realized.

The invention relates to a double-layer uniform grating capable of realizing high-efficiency transmission-type large-angle deflection of 3D printing, and belongs to the technical field of novel artificial electromagnetic materials and terahertz science. The grating structurally comprises three layers, the lower layer is a uniform medium grating (1), the middle layer is a medium spacing layer (2), and the upper layer is a uniform medium grating (3) which has the same period with the lower layer but has different duty ratios with the lower layer. Each of the upper layer and the lower layer only comprises one grid structurein each period, and one side of the upper grid and one side of the lower grid are kept flush to form an asymmetric double-layer grating. By properly selecting the period of the grating and the size of internal grating bars, vertically incident sub-terahertz waves can be efficiently transmitted and deflected to a large-angle direction close to the surface of the grating. The grating is easy to design and process, can be quickly formed by using a 3D printing technology, is low in cost, and provides a new scheme for the development of extreme sub-terahertz functional devices.

The invention discloses a method for improving the water flux of a composite forward osmosis membrane. The method comprises the following steps: (1) putting a base membrane of a forward osmosis membrane into a water solution of an organic solvent and carrying out immersion treatment; (2) taking out the base membrane subjected to the immersion treatment and washing with clean water; (3) preparing aseparation layer on the base membrane through interface polymerization, so as to obtain a high-flux polyamide composite forward osmosis membrane. According to the method provided by the invention, the organic agent is used for immersing so that a pore wall of the base membrane becomes thin, a pore structure is changed and the sinuosity of a membrane pore is small; meanwhile, the porosity of the base membrane is improved and the quantity of large finger-shaped holes is also increased, so that structural parameters of the membrane are reduced and an inner concentration difference polarization phenomenon of the forward osmosis membrane is reduced; finally, the water flux of the composite forward osmosis membrane is improved. The method provided by the invention is simple and the operation iseasy to realize, so that the method is especially suitable for large-scale industrial production.

The invention relates to a single-pointed coaxially feeding lowly-outlined cavity-backed circularly polarized antenna. The common cavity-backed circularly polarized antenna has a complex structure, large size, and a high manufacturing cost. In the invention, a metal layer is plated on the two faces of the dielectric substrate; an upper metal layer is etched with two strips of vertical rectangularslots used for radiating the energy. A plurality of plated-through holes aligned circularly is installed by penetrating the upper metal layer, the dielectric substrate and a lower metal layer, thus forming a round cavity. A coaxial probe as a feeding structure is introduced by penetrating the lower metal layer and the dielectric substrate at the proper location of an angular bisector of the two strips of vertical rectangular radiating slots in the cavity region. Compared with the cavity-backed circularly polarized antenna formed by the existing metal cavity, the cavity adopted by the invention is manufactured by the common PCB technology, thus downsizing the antenna outline and reducing the manufacturing cost.

The invention relates to an H-plane sectorial horn antenna with the function of a filter. The existing horn antenna that can not be planar integrated has a large size and a high processing cost. In the invention, a metal layer is plated at two faces of a dielectric substrate, and an upper metal layer is etched with a micro-strip line used for feeding and a micro-strip converter. A plurality of plated-through holes aligned circularly are installed by penetrating the upper metal layer, the dielectric substrate and a lower metal layer, thus forming a substrate integrated waveguide and an H-planesectorial horn. Four perturbation plated-through holes are installed by penetrating the whole substrate on the medial axis inside the opening area of the H-plane sectorial horn, used for regulating the impedance matching and forming the filtering function. The new structure adopts the substrate integrated waveguide technology, so that the function equivalent to traditional metal H-plane sectorialhorn is implemented on the normal dielectric substrate, meanwhile the filtering function of the traditional inductive post waveguide filter is successfully integrated. The dual-function integrated module is very compact in size; the whole structure can be manufactured by low cost PCB technology, and can seamlessly integrate with the system.

The invention relates to an optimization modeling method of an electro-magnetic doubly salient reluctance motor. The method comprises the following steps: selecting a plurality of optimization targets according to an application scene of the motor; selecting the first n structural parameters with the maximum numerical values from the structural parameters of the motor body by calculating the comprehensive sensitivity index; each parameter structure is preset to have M selection levels, and Mn groups of parameter modeling samples can be obtained; normalizing all parameter modeling samples, and randomly dividing the parameter modeling samples into a training set and a test set according to a set proportion; and carrying out machine learning on the training set and a set optimization target by utilizing a KNN algorithm, establishing a motor optimization model, and checking the accuracy of the established motor optimization model through the test set. Compared with the prior art, the method has the advantages that the comprehensive sensitivity index is introduced to reduce the structural parameters of the motor body, the parameter modeling sample space is greatly reduced, the data required by the sample is effectively reduced, the modeling speed is increased, and the requirement of the industry for rapid optimization of the motor is met.

The invention discloses a same-direction-engaged Lelo triangular rotor pump. The pump mainly comprises a rotor pump shell, three identical Lelo triangular rotors, a driving gear, three driven gears, a front pump cover, a back pump cover and the like. The three Lelo triangular rotors are mounted in a pump body in parallel, and are fixedly connected with the three driven gears on the outer side of the pump body; the driving gear drives the driven gears and the three Lelo triangular rotors to rotate in the same direction to form an oil sucking cavity and an oil pressing cavity; and an oil inlet and an oil outlet are formed in the rotor pump shell. The same-direction-engaged Lelo triangular rotor pump has the following beneficial effects: the linear oil way oil pumping can be realized to shorten the oil pumping route; the pitch of an inclined rotor is changed to control the flow pulsation change, so that the application of the same-direction-engaged Lelo triangular rotor pump to the field of vibration machinery is possible; and the three Lelo triangular rotors are spiral rotors, and an area surrounded by the rotors and the pump body can realize the propeller type oil pumping, so that the rotors cannot be contacted with the inner wall of the pump body to realize the purpose of reducing frictional loss.

The invention discloses a broadband frequency selector and mainly solves the problems in the prior art that the unit size is large and the performance is poor during the large-angle incidence of an electromagnetic wave. The broadband frequency selector comprises a metal layer (1) and a medium layer (2), wherein the metal layer is positioned on the medium layer and consists of N hexagonal units (11) which are periodically arranged according to a triangular grid; N is more than or equal to 3; each unit comprises a regular hexagon metal patch (111) and a regular hexagon metal wire frame (112) at the periphery of the regular hexagon metal patch (111) and a regular hexagon gap (113) is arranged between the metal patch and the corresponding metal wire frame; an H-shaped gap (114) is vertically etched in the center of each edge of each regular hexagon gap; the H-shaped gaps are of the same size; and each H-shaped gap comprises two vertical seams of the same size and a horizontal gap which is sandwiched between the two vertical seams. The broadband frequency selector can maintain the stability of a central frequency point and high frequency selection characteristic during the incidence of the electromagnetic wave at an angle of 0 to 70 DEG, has the advantages of broad working frequency band, low loss, simple structure and easiness in implementation, and can be applied to radar domes and parabolic antennae.

The invention is a quasi-elliptic filter characteristic frequency selection surface, an ultrathin novel frequency selection surface with quasi-elliptic filter characteristic, based on substrate integrated waveguide cavity cascading technique, and the structure is made on a multilayer substrate formed by laminating three layers of microwave plates and having four metal surface layers and three medium layers, where the top and bottom metal surfaces are made with periodical square annular slots of the same size. And the intermediate metal surface is made with periodical square annualr slots of the other size which coincides the centers of the square annular slots on the top and bottom surfaces, three medium layers are filled in between the four metal surface layers, and a series of metalized through holes are arranged at regular intervals around each periodical square annular slot unit on the ready-laminated multilayer substrate so as to form a substrate integrated waveguide cavity equivalent to traditional metal cavity. As compared with common SMD or slot type multiscreen cascaded frequency selection surface, it first implements quasi-elliptic filter performance with high selectivity.

The invention belongs to the technical field of nanometer materials, and particularly relates to a preparation method of a polymer core nano ring of a core-shell structure. According to the invention,amphiphilic block polymer (wherein one block is hydrophobic poly(4-vinylpyridine) or hydrophobic amine polymer) and annular DNA are taken as raw materials, and the hydrophobic block is firstly complexed with DNA in a protonated water / methanol (or a good solvent of an amine polymer) environment, poor solvent water is continuously added, the block polymer forms the nano ring using hydrophobic polypoly(4-vinylpyridine) or hydrophobic amine polymer as the core. The method can be used for preparing the polymer nano rings with the tailored core-shell structure with different sizes, the preparationprocess is simple and convenient, and the core of the polymer nano ring can be subjected to functional modification, so that the hybrid of the polymer nano ring can be realized, and the polymer nano ring can be used as a template to prepare the composite material with excellent performances.