Abstract: The present invention discloses an iterative learning control (ILC) method for a multi-particle vehicle platoon driving system, and relates to the field of ILC. The method includes: firstly, discretizing a multi-particle train dynamic equation using a finite difference method to obtain a partial recurrence equation, and then transforming the partial recurrence equation into a spatially interconnected system model; secondly, transforming the spatially interconnected system model into an equivalent one-dimensional dynamic model using a lifting technology, and in order to compensate input delay, designing an ILC law based on a state observer; and thirdly, transforming a controlled object into an equivalent discrete repetitive process according to the ILC law, and converting a controller combination problem into a linear matrix inequality based on stability analysis of the repetitive process.

Abstract: Disclosed is a roller taper grinding method for a planetary roller screw mechanism. The method includes steps as follows: step 1: determining basic parameters and a bearing capacity of a planetary roller screw mechanism to be machined; step 2: establishing deformation and force balance equations of the planetary roller screw mechanism according to the basic parameters and the bearing capacity of the planetary roller screw mechanism determined in step 1; step 3: iteratively computing an optimal grinding taper angle of roller grinding according to the deformation and force balance equations established in step 2; step 4: determining process parameters of roller grinding; and step 5: grinding a roller taper of the planetary roller screw mechanism by a machine tool according to the process parameters determined in step 4.

Abstract: Provided is a preparation method of a detector material. The present disclosure epitaxially grows a buffer layer on a surface of a gallium arsenide substrate, deposits a silicon dioxide layer on the buffer layer, and etches the silicon dioxide layer on the buffer layer according to a strip pattern by photolithography and etching to form strip growth regions with continuous changes in width. Finally, a molecular beam epitaxy (MBE) technology is used to epitaxially grow the detector material in the strip growth regions under set epitaxy growth conditions. Because of the same mobility of atoms arriving at the surface of the substrate, numbers of atoms migrating to the strip growth regions are different due to different widths of the strip growth regions, such that compositions of the material change with the widths of the strip growth regions or a layer thickness changes with the widths of the strip growth regions.

Abstract: A rare earth permanent magnet, and a preparation method therefor are provided. The rare earth permanent magnet M and the preparation method may effectively improve the grain boundary anisotropy of the magnet, provide more diffusion channels through which a heavy rare earth diffusion source can enter the inside of the magnet, such that the heavy rare earth diffusion source is more effectively diffused into the magnet, the intrinsic coercivity of the magnet is greatly improved, and a magnet N having high intrinsic coercivity is obtained. Using the same amount of a heavy rare earth diffusion source material, the method produces magnet N having high intrinsic coercivity amplification with reduced production costs.

Abstract: The permanent magnet comprises a main phase structure of R2T14B crystal grains, and R is a rare earth element; T comprises at least Mn, Fe, and optionally a transition metal comprising Co; B is boron; the permanent magnet further comprises Mn and heavy rare earth elements which are distributed in a grain boundary in a diffusion mode. The heavy rare earth element is selected from at least one selected from Dy, Ho and Tb. According to the rare earth permanent magnet prepared through the preparation method, more heavy rare earth elements can be diffused into the magnet core along the grain boundary, Hcj distribution of the permanent magnet is improved, and meanwhile the corrosion resistance and the mechanical property of the permanent magnet are improved.

Abstract: The present disclosure discloses a laser radar for meteorological observation, and specifically relates to the field of meteorology. The laser radar comprises a base. According to the present disclosure, air pressure at the bottom of 301 is increased by injecting gas into the interior of 202, so that the 301 falls off from 201, and the disassembly between the stable seat and the connecting sleeve plates is realized; with regard to the disassembly process of the connecting sleeve plates and the base, the magnetic pole of a positioning electromagnet is changed mainly by switching the current direction of an external coil of the positioning electromagnet, so that the positioning electromagnet is separated from the locking magnet, thereby facilitating the detachment of the base and the connecting sleeve plates in combination with the linkage component, and the disassembly process of the whole device.

Abstract: The present disclosure discloses a laser radar for meteorological observation, and specifically relates to the field of meteorology. The laser radar comprises a base. According to the present disclosure, air pressure at the bottom of 301 is increased by injecting gas into the interior of 202, so that the 301 falls off from 201, and the disassembly between the stable seat and the connecting sleeve plates is realized; with regard to the disassembly process of the connecting sleeve plates and the base, the magnetic pole of a positioning electromagnet is changed mainly by switching the current direction of an external coil of the positioning electromagnet, so that the positioning electromagnet is separated from the locking magnet, thereby facilitating the detachment of the base and the connecting sleeve plates in combination with the linkage component, and the disassembly process of the whole device.

Abstract: The present disclosure relates to a field stage lighting, in particular to an LED projection lamp. The LED projection lamp includes an optical lens cover, a first aluminum substrate, a second aluminum substrate, and a first housing. A first glass lens bracket, a glass lens, and a second glass lens bracket are respectively arranged on an upper end of the first aluminum substrate. A water ripple sheet is arranged on a lower end of the first aluminum substrate. Condensing lens is arranged on an upper end of the second aluminum substrate. A motor is arranged on a lower end of the second aluminum substrate. A second housing is arranged on a lower end of the first housing.

Abstract: A method for preparing an R—Fe—B based sintered magnet. The method includes: 1) preparing a R1—Fe—B-M alloy, pulverizing the R1—Fe—B-M alloy to yield a R1—Fe—B-M alloy powder, adding a heavy rare earth powder of R2 or R2X and subsequently adding a lubricant to the R1—Fe—B-M alloy powder and uniformly stirring to form a mixture, where R1 being Nd, Pr, Tb, Dy, La, Gd, Ho, or a mixture thereof; M being Ti, V, Cr, Mn, Co, Ga, Cu, Si, Al, Zr, Nb, W, Mo, or a mixture thereof; R2 being at least one from Tb, Dy, and Ho; X being at least one from O, F, and Cl; 2) pressing the mixture obtained in step 1) to form a compact, and sintering the compact in a pressure sintering device in vacuum or in an inactive gas atmosphere to obtain a magnet; and 3) aging the magnet obtained in step 2).

Abstract: An electronic device implementing a point cloud system is configured to simplify a mesh point cloud. The point cloud system obtains a mesh point cloud from a mesh cloud file uploaded to the electronic device, and obtains information of a number of triangles formed by the mesh point cloud. A unit normal vector of each vertex point of each triangle is calculated, and a decision value of each vertex point of each triangle is calculated. The vertex points of each triangle are classified into a number of classification levels according to the decision values. A number of sample vertex points from each of the classification levels is selected, and a triangular structure of the sample vertex points is restored to obtain a simplified mesh point cloud.

Abstract: A computing device and a method of processing point clouds of an object. Two groups of point clouds are selected as a first and a second group of point clouds. Redundant points in the first and second groups of point clouds are determined and marked using a first indicator. Normal points are determined in the second group of point clouds and marked using a second indicator. The method further uses a plurality of cubes for dividing the redundant points marked with the first indicator, and clears a first indicator of a specified redundant point in each of cubes which has a minimum distance to a centre point of the each of cubes. The method merges points which have not been marked with the first indicators in the first and second groups of point clouds to be a new group of point clouds.

Abstract: A method for reducing a point cloud includes receiving a mesh point cloud file uploaded to an electronic device and obtaining a number of data points of the point cloud from the mesh point cloud file, calculating a bounding box of the point cloud from the number of data points, dividing the bounding box into a number of cubes, determining effective cubes of the plurality of cubes, calculating a mean curvature of each of the effective cubes, determining a type of each of the effective cubes according to the mean curvature, reducing each effective cube according to the type of the effective cube to obtain a post-reduction cube, combining the post-reduction cubes to obtain a post-reduction point cloud, and restoring a mesh point cloud of the point cloud according to the post-reduction point cloud. An electronic device for reducing a point cloud is also provided.

Abstract: An electronic device having a processing unit and storage device receives point cloud data, and divides a bounding box of the point cloud data into a plurality of segmented boxes. Then, the processing unit selects a plurality of data boxes each having at least one point from the segmented boxes and assigns a reference value to each such point in the data boxes. The processing unit selects initial sampling points from the points in the data boxes, based on the reference values, to form a sample point cloud and adds to or subtracts from the sample point cloud based on the number of initial sampling points and a predetermined sampling rate.

Abstract: A method for preparing an R—Fe—B based sintered magnet. The method includes: 1) preparing a R1—Fe—B-M alloy, pulverizing the R1—Fe—B-M alloy to yield a R1—Fe—B-M alloy powder, adding a heavy rare earth powder of R2 or R2X and subsequently adding a lubricant to the R1—Fe—B-M alloy powder and uniformly stirring to form a mixture, where R1 being Nd, Pr, Tb, Dy, La, Gd, Ho, or a mixture thereof; M being Ti, V, Cr, Mn, Co, Ga, Cu, Si, Al, Zr, Nb, W, Mo, or a mixture thereof; R2 being at least one from Tb, Dy, and Ho; X being at least one from O, F, and Cl; 2) pressing the mixture obtained in step 1) to form a compact, and sintering the compact in a pressure sintering device in vacuum or in an inactive gas atmosphere to obtain a magnet; and 3) aging the magnet obtained in step 2).