38results about How to "Has rotational symmetry" patented technology

The invention discloses an unshielded three-reflector optical system, which can be used in a wide spectral imaging system with wave band from ultraviolet to infrared, and is particularly applicable to a preposed object lens of a spectrum imager. The system consists of a main reflector, a secondary reflector and a third reflector with aperture ratio of 1 / 0.5-1 / 3; the system avoids shielding through inclining elements; a beam path of the system is telecentric beam path in the image side; a principle ray of zero field coverage is spread along links of the vertex of each element; a diaphragm is arranged on the secondary reflector; the secondary reflector is arranged on a focal plane of the third reflector; focal power of the main reflector, the secondary reflector and the third reflector is positive, negative and positive respectively; curvature radiuses of the vertexes of the three reflectors approximately meet the condition of Petzval; and types of the three reflectors are Zernike free surfaces. The system has reasonable residual aberration distribution to greatly improve image quality, and can easily avoid shielding, so that the effective use area of each mirror face is equivalent to an original mirror; and the primary ray of the zero field coverage of the system moves along the links of the vertex of each surface, thereby facilitating the processing, assembly and regulation of the system.

The invention provides a liquid crystal lens array and a stereoscopic display apparatus, and relates to the technical field of stereoscopic display. The liquid crystal lens array includes a plurality of liquid crystal microlens units, wherein each liquid crystal microlens unit includes a first glass substrate and a second glass substrate; the first glass substrate is plated with a first electrode; the second glass substrate is plated with a second electrode; liquid crystal is filled between the first glass substrate and the second glass substrate; and the first electrode includes a circular electrode at the center position, and at least two annular electrodes which are arranged in the shape of a concentric ring and take the circular electrode as the center. As the 3D display effect formed by the liquid crystal lens array has no directionality, a user can watch the required 3D effect from a wider angle, and the watching angle is more continuous, so that the 3D display effect of a stereoscopic display apparatus using the liquid crystal lens array becomes better and has no shear zones and the problem that the watcher becomes giddy because of being in the shear zone is effectively avoided.

The invention discloses a novel topological photonic crystal structure and an optical waveguide, and a unit cell of the novel topological photonic crystal structure is formed by arranging six identical dielectric cylinders into two independent regular triangle units and has C3 rotational symmetry. A plurality of structural states of the crystal structure all have a dual Dirac cone cell, and energyband inversion and topological phase transition are achieved by stretching and compressing at least one of the two triangular units on the basis of each cell state having a dual Dirac cone, and a large topological non-mediocre photonic band gap is opened. An optical waveguide is also constructed based on the crystal structure, the topological non-mediocre photonic crystal (PC3) and the topological mediocre photonic crystal (PC1) are combined to support optical unidirectional transmission at the interface to inhibit backscattering, the transmission efficiency is extremely high, the immunity tostructural defects is strong, and three different structural defects can be perfectly passed.

The invention provides a low-grating lobe configuration method of a three-dimensional imaging radar two-dimensional sparse array. According to the method, a plurality of rotating arms are adopted, and strong grating lobes caused by a sparse array can be inhibited, and the inhibition performance of an imaging radar for false targets can be improved. The method includes the following steps that: the number of array elements contained by each rotating arm and the total number Narm of rotating arms are determined according to a given total number of array elements; one rotating arm is designed according to a Fibonacci array, the positions of array elements are represented by polar coordinates (r, theta), wherein the radius r is the linear function of the square root of the serial number of the array elements, and the angle theta of the array elements is increased linearly with the serial number of the array elements; and the rotating arm is rotated around the center of the array by 2pik / Narm(k=1,...,Narm-1), and a final array can be obtained. According to the method of the invention, the multi-rotating arm array of a rotary and symmetrical structure is designed, the number of array elements of which the projections are overlapped in any directions is small, and therefore, the problem of array element masking of a conventional two-dimensional array configuration method can be well solved, and a directional diagram with a low grating lobe level can be obtained, and detection for targets can be benefitted, and false targets can be inhibited.

The invention relates to a DMD spatial dimension coding symmetric Offner dispersion medium wave infrared spectral imaging device, and belongs to the technical field of infrared spectral imaging. The prior art has the disadvantages that the prior art cannot satisfy the demand for all-weather spectral imaging; the spatial resolution and the spectral resolution are low; the adopted microlens array process is complicated and difficult to process; and the adopted planar grating may cause spectral line bending and color distortion problems. The DMD spatial dimension coding symmetric Offner dispersion medium wave infrared spectral imaging device is characterized in that a working plane of a medium wave infrared DMD is located at an image plane of a medium wave infrared achromatic varifocal objective set; an object plane of a symmetric Offner dispersion system coincides with the image plane of the medium wave infrared achromatic varifocal objective set; a refrigeration medium wave infrared detector is arranged on an emitting optical path of the symmetric Offner dispersion system; and a photosensitive surface of the refrigeration medium wave infrared detector is located at the image plane of the symmetric Offner dispersion system; in the symmetric Offner dispersion system, a spherical reflector and a spherical reflection grating have the same curvature center; and the refrigeration medium wave infrared detector is connected with an image acquisition card, and the image acquisition card, a computer and the medium wave infrared DMD are sequentially connected.

The invention discloses a light-emitting diode (LED) indoor illumination optical lens, which is of a rotary symmetrical structure, wherein a concave hemispherical surface which makes the LED emergent ray enter the lens without deflection is arranged at the bottom of the optical lens, an LED is installed at the sphere center of the hemispherical surface, the external surface of the optical lens is a free-form surface which controls the direction of the LED emergent ray and has continuously changed curvature, the radius of the hemispherical surface is 1 / 3R to 1 / 2R, wherein R is the radius of the bottom of the optical lens. The LED indoor illumination optical lens has a simple structure, reasonable design, uniform LED illumination, high illumination efficiency, widened LED utilization scope, is energy-saving and environmental-friendly, has a good use effect, and is convenient to popularize and use.

The invention discloses a hardware Trojan horse image registration method based on RSIFT, a storage medium and equipment, and the method comprises the steps: carrying out the Gaussian filtering and down-sampling of an input image, and constructing a multi-scale space; detecting an extreme point of the image in the constructed multi-scale space; assigning values to the directions of the obtained extreme points to obtain position, scale and direction information of the corresponding points, and generating feature descriptors; preliminarily generating a pre-matching point pair by using the generated feature descriptor and a distance matching method, and representing the pre-matching point pair by using a matching matrix C; and after the pre-matching matrix C is determined, performing correction by using an RANSAC algorithm, removing redundant matching points, and completing image registration. According to the invention, the problem of affine transformation in image registration is effectively solved, interference caused by noise points can be avoided more flexibly, and the stability and accuracy of the image registration method are further improved.

The invention provides a phased-array antenna unit with flat-top directional diagram characteristics. The phased-array antenna unit comprises a metallic waveguide area and a free space area, wherein the metallic waveguide area is composed of a cylindrical waveguide and a conical waveguide connected with the cylindrical waveguide, a micro-strip plate laminating cylinder conformal array used for achieving flat-top wave beam unit directional diagram shape design through slot coupling is arranged on a port of the conical waveguide, evenly distributed eccentric round metal sheets are etched on each layer of micro-strip plates and arranged into a matrix, an light insulator is arranged on a cascaded superposition slot area of every two adjacent micro-strip plates, and then a free space area multi-layer conformal array unit is formed. The phased-array antenna unit has the advantages that the structure is simple, rotary symmetry is adopted for the structure, directional diagram equalization performance is good in the electric aspect, the unit can be applied to both linear polarization and circular polarization, external grating lobes generated during array scanning can be effectively restrained, margin gain of scanning can be improved, and the design method can be applied to a limited scanning two-dimensional phased-array antenna unit with a wide scanning range.

The invention discloses a method for automatically generating a decorative pattern expansion drawing of rotating symmetric porcelain. The method comprises the steps of first, inputting data information of a model with a two-dimensional texture; second, acquiring an erected model based on a symmetry axis rotating model, and thus acquiring front view of the erected model in the front, rear, left and right directions; third, analyzing the four acquired front views by using a gradient operator so generate a cumulative gradient map of the model; fourth, calculating a model cutting plane on the basis of the acquired cumulative gradient map so as to complete segmented processing for the model; and fifth, performing circular truncated cone fitting on each acquired segmented model; and sixth, judging whether a texture-free special region exists or not in circular truncated cone fitting, and if so, combing the texture-free region with a generated circular truncated cone; and otherwise, expanding the texture at the surface of the circular truncated cone, and generating a planar decorative pattern expansion drawing. Disclosed by the invention is a novel technology in which a decorative pattern at the surface of the porcelain is expanded to a two-dimensional plane from the surface of a three-dimensional utensil based on a method of surface parameterization.

The invention discloses a wave-absorbing surface with low profile and low incidence angle sensitivity. The wave-absorbing surface comprises a dielectric substrate, a two-dimensional plane periodic array printed on the front surface of the dielectric substrate and formed by arranging lossy frequency selection units, and a metal back plate, and the lossy frequency selection unit is formed by nesting a resistive square ring patch with an interdigital edge and a metal square patch. According to the invention, the wave absorbing rate can reach more than 90% in the working frequency band, and good performance stability can be maintained for incident electromagnetic waves with TE and TM polarization, a pitching incident angle in a range of 0-40 degrees and an incident angle in any direction. Compared with the prior art, the wave-absorbing surface has the advantages of being extremely low in profile, light in weight, convenient to process, high in wave absorbing rate in a working frequency band, good in polarization stability and angle stability and good in engineering application prospect.

The invention discloses a low-profile dual-band wave-absorbing surface applied to a vehicle-mounted radar test environment. The low-profile dual-band wave-absorbing surface comprises a dielectric substrate, an array printed on the front surface of the dielectric substrate and formed by periodically arranging resistive frequency selection units, and a metal floor printed on the back surface of the dielectric substrate, and the resistive frequency selection unit is composed of a resistive square ring and a resistive square patch, and the square patch is embedded in a hollow area of the square ring. According to the invention, effective absorption of electromagnetic waves can be realized in two vehicle-mounted radar frequency bands of 24GHz and 77GHz for omnidirectional angles, pitch angles within 30 degrees, TE polarized incident waves and TM polarized incident waves. Compared with the prior art, the low-profile dual-band wave-absorbing surface has the advantages of extremely low profile, light weight and simplicity and convenience in processing and mounting, can effectively eliminate the interference of stray electromagnetic waves when being applied to a vehicle-mounted radar test environment, can greatly reduce the occupied space of a test system, and has a very good engineering application prospect.

The invention discloses a road sign identification method based on generalized Hough transform and wavelet transform. The method includes the following steps: step one, selecting standard images to construct a feature image library; step two, denoising the collected images; step three, conducting generalized Hough transform on the denoised images to perform edge extraction; step four, extracting low frequency information of the extracted images through wavelet decomposition; step five, establishing corresponding feature images on the basis of the low frequency information of the images; and step six, utilizing Euclidean distance to carry out matching identification on the established feature images and the feature image library. According to the invention, the low frequency information ofthe images is obtained through wavelet decomposition so that the feature image library is established, and the most essential feature information having the best identification effect in the images iskept. Compared with a conventional identification method, the method is higher in accuracy.

The invention relates to a source arrangement of a VPE deposition device, comprising a container (2) containing a liquid or solid starting material (1) and having a top opening, a feed line (3) for a reactive gas (4) which reacts with the starting material (1) in order to produce a process gas (5) that contains the starting material. The aim of the invention is to temporally stabilize the source reaction. For this purpose, a cover (6) rests directly on the starting material (1) and defines a volume (8) between the cover and the surface (7) of the starting material (1), the reactive gas (4) flowing through said volume and the feed line (3) running into it.

The invention discloses an unshielded three-reflector optical system, which can be used in a wide spectral imaging system with wave band from ultraviolet to infrared, and is particularly applicable to a preposed object lens of a spectrum imager. The system consists of a main reflector, a secondary reflector and a third reflector with aperture ratio of 1 / 0.5-1 / 3; the system avoids shielding through inclining elements; a beam path of the system is telecentric beam path in the image side; a principle ray of zero field coverage is spread along links of the vertex of each element; a diaphragm is arranged on the secondary reflector; the secondary reflector is arranged on a focal plane of the third reflector; focal power of the main reflector, the secondary reflector and the third reflector is positive, negative and positive respectively; curvature radiuses of the vertexes of the three reflectors approximately meet the condition of Petzval; and types of the three reflectors are Zernike free surfaces. The system has reasonable residual aberration distribution to greatly improve image quality, and can easily avoid shielding, so that the effective use area of each mirror face is equivalent to an original mirror; and the primary ray of the zero field coverage of the system moves along the links of the vertex of each surface, thereby facilitating the processing, assembly and regulation ofthe system.

The invention provides a horizontal omnidirectional displacement amplification type SMA energy dissipation and seismic mitigation device, and belongs to the technical field of structural vibration control. The device is composed of a top plate, a spherical ring, a gourd-shaped rotating ball body, a high-strength bolt, a lever arm, a hollow circular truncated cone, an SMA stranded wire, a U-shapedlocking ring, a bottom plate, a fastening clamp, a spring bolt and the like. According to the device, through the omnidirectional rotation capacity of the gourd-shaped rotating ball body, the device can still utilize hysteretic deformation of the SMA stranded wire to consume energy under the effect of random and unpredictable multidirectional earthquake, and therefore 360-degree omnidirectional effective damping is provided. Meanwhile, the device amplifies the relative displacement of a pier beam of a bridge structure through a lever spherical hinge rotating mechanism, so that the displacement, speed and other responses of the series energy dissipation material are amplified, and the device can play a good energy dissipation role under the effect of large, medium and small earthquakes. Thedevice is clear in structure and high in applicability, and is a safe and efficient energy dissipation and seismic mitigation device.

The invention relates to a solenoid valve, in particular for controlling a brake pressure of a wheel brake of a motor vehicle, comprising an axially moveably mounted armature, wherein one end of the armature is associated with a pole core and a valve sealing element is arranged at another end of the armature, wherein the armature has an axial through-opening, wherein a closure element is force-lockingly and / or interlockingly retained in the axial through-opening in a selectable position, and a plunger is axially moveably mounted in the axial through-opening, which provides a connection to thepole core in an installation position, wherein a pressure spring is positioned in the axial through-opening, wherein the pressure spring is retained in a pretensioned manner between the plunger and the closure element, characterised in that the closure element is designed as a three-dimensionally convex element.

A first substrate includes, on one side thereof that is closer to a liquid crystal layer, a picture element electrode provided for each picture element region, a switching element, and a bus line. A second substrate includes a counter electrode opposing the picture element electrode. The picture element electrode includes a plurality of openings and a solid portion that includes a plurality of unit solid portions. In each picture element region, the liquid crystal layer takes a vertical alignment in the absence of an applied voltage, and forms a plurality of liquid crystal domains, each of which takes a radially-inclined orientation, in the plurality of openings and the solid portion by inclined electric fields produced at respective edge portions of the plurality of openings of the picture element electrode in response to an applied voltage. In each picture element region, at least one of the plurality of openings of the picture element electrode that is located along the bus line and located between two adjacent ones of the plurality of unit solid portions is superposed on the bus line.

The invention relates to a method for calculating an orientation system structure factor in SAXS calculation. The method comprises acquisition: acquiring length-diameter ratios of scatterers subjectedto SAXS synchrotron radiation light source irradiation, determination: determining structure factor calculation formulas of different scatterers according to the length-diameter ratios and calculation: respectively calculating structure factors of the different scatterers according to the different calculation formulas. The invention also relates to a system for calculating an orientation systemstructure factor in SAXS calculation. The method and system can acquire more precise structure factors of scatterers of the more dense orientation system and provide good data support for the non-destructive detection of the effectively observed material mesoscopic scale structure based on small-angle X-ray scattering SAXS.

The invention discloses a small-size high-isolation three-unit MIMO antenna based on a printed circuit board. The antenna comprises a substrate, slot antenna bodies with an open-loop terminal and a micro-strip feed circuit with a micro-strip decoupling structure. The substrate is a double-face printed circuit board with a rotational symmetry structure, the micro-strip feed circuit is etched on the front face of metal of the substrate, the slot antenna bodies are etched on the reverse side of the substrate, the substrate is provided with feed through holes used for feed and short-circuit through holes used for matching, the micro-strip feed circuit is composed of standard micro-strip feeder lines and the corresponding micro-strip decoupling structure, and the micro-strip feeder lines pass through the slot antenna bodies, carry out feed on the slot antenna bodies through coupling and are matched with the short-circuit through holes; the micro-strip decoupling structure is connected with the micro-strip feeder lines to provide a new coupling component for offsetting an original coupling component of the connecting position so as to achieve decoupling. The size of the antenna is reduced, high isolation and directional radiation characteristics are achieved, and the antenna can be applied to small-sized wireless communication equipment with the MIMO technology adopted.

The invention discloses a switching type broadband terahertz wave absorber based on VO2. The switching type broadband terahertz wave absorber comprises a plurality of microstructure units arranged ina matrix form; each microstructure unit comprises a phase change material layer, a dielectric layer and a reflecting layer; the phase change material layer is located on the upper surface of the dielectric layer, and the reflecting layer is located on the lower surface of the dielectric layer; the phase change material layer comprises four L-shaped VO2 patches arranged in a matrix form; the middleof the L-shaped VO2 patch is hollowed out, and a hollowed-out pattern is in an L shape which is shrunk in proportion; wherein two long arms of each L-shaped VO2 patch extend towards the edge direction of the phase change material layer, and any two adjacent L-shaped VO2 patches are in mirror symmetry. The absorption bandwidth and the absorption rate of the switch type terahertz wave absorber canbe improved, and the design and preparation difficulty of the switch type terahertz wave absorber is not increased.

The invention provides a liquid crystal lens array and a stereoscopic display apparatus, and relates to the technical field of stereoscopic display. The liquid crystal lens array includes a plurality of liquid crystal microlens units, wherein each liquid crystal microlens unit includes a first glass substrate and a second glass substrate; the first glass substrate is plated with a first electrode; the second glass substrate is plated with a second electrode; liquid crystal is filled between the first glass substrate and the second glass substrate; and the first electrode includes a circular electrode at the center position, and at least two annular electrodes which are arranged in the shape of a concentric ring and take the circular electrode as the center. As the 3D display effect formed by the liquid crystal lens array has no directionality, a user can watch the required 3D effect from a wider angle, and the watching angle is more continuous, so that the 3D display effect of a stereoscopic display apparatus using the liquid crystal lens array becomes better and has no shear zones and the problem that the watcher becomes giddy because of being in the shear zone is effectively avoided.

The invention discloses a DMD spatial dimension coding symmetric Offner dispersive dual-color infrared spectral imaging device, which belongs to the technical field of infrared spectral imaging. All-weather w spectral imaging needs can not be met in the prior art. The DMD spatial dimension coding symmetric Offner dispersive dual-color infrared spectral imaging device is characterized in that the working plane of a dual-color infrared DMD is located at an image plane of a dual-color infrared achromatic zoom object lens group; the object plane of a symmetric Offner dispersive system is coincident with the image plane of the dual-color infrared achromatic zoom object lens group; in the symmetric Offner dispersive system, a spherical reflector and a spherical reflective grating have the same curvature center; a dual-color infrared spectroscope is arranged in an emergent light path of the symmetric Offner dispersive system and an angle of 45 DEG is formed with the light axis of the light path; two splitting light paths of the dual-color infrared spectroscope are provided with a refrigerated medium wave infrared detector and a long wave infrared detector; light-sensitive planes of the refrigerated medium wave infrared detector and the long wave infrared detector are located on the image plane of the symmetric Offner dispersive system; the two detectors are connected with an image acquisition card respectively; the image acquisition card, a computer and the dual-color infrared DMD are sequentially connected; and the dual-color infrared light refers to 3 to 5 mum and 8 to 14 mum.

The invention relates to a source arrangement of a VPE deposition device, comprising a container (2) containing a liquid or solid starting material (1) and having a top opening, a feed line (3) for a reactive gas (4) which reacts with the starting material (1) in order to produce a process gas (5) that contains the starting material. The aim of the invention is to temporally stabilize the source reaction. For this purpose, a cover (6) rests directly on the starting material (1) and defines a volume (8) between the cover and the surface (7) of the starting material (1), the reactive gas (4) flowing through said volume and the feed line (3) running into it.

Disclosed is a small-sized transceiving shared broad-wave-beam coverage antenna. The coverage antenna comprises an antenna radiator, an octagonal-prism table and octagonal-prism column structure, a built-in transceiving assembly, a bottom plate, radio-frequency connectors, a low-frequency connector and an octagonal-prism table upper cover plate, wherein the antenna radiation body comprises eight receiving antenna units and eight transmitting antenna units, and a group of receiving and transmitting units are arranged on the side surface of each prism table; the octagonal-prism table and octagonal-prism column structure adopts an integrated structure with the octagonal-prism table on the upper part and the octagonal-prism column on the lower part; the built-in transceiving assembly comprises a receiving assembly and a transmitting assembly; the bottom plate is used for fixing the built-in transceiving assembly; and the radio-frequency connectors comprise a transmitting radio-frequency connector and a receiving radio-frequency connector. The characteristics of small size, transceiving sharing, and high-gain coverage performance of 5dBi in a broad-wave-beam coverage region at a pitching angle of minus or plus 70 degrees is realized by virtue of the crossed array design of the receiving and transmitting antenna units on the adjacent side surfaces of the octagonal-prism table, 16 oval-like wave beam wide coverage wave beam design and small-sized comprehensive design.