16 results about "Tetrahedron" patented technology

The utility model discloses a kind of splicing ornaments, belong to ornament technical field, including multiple splicing modules, the splicing module is triangle or square, its edge is equipped with zip structure, and splicing module can be connected by the zip structure between it. Through different combination mode, the splicing module can be assembled to form the ornament of tetrahedron structure, hexahedron structure or four pyramid structure. The splicing module is equipped with hole, for wearing external chain to realize the function of suspension. The utility model connects between splicing module by zip structure, with the characteristics of convenient splicing, combination form is various.

This invention discloses a method for inverse kinematics modeling of a polyhedral mobile robot, comprising: S1, constructing a forward kinematics model of a polyhedral open-chain robot, defining a kinematic space with the edge lengths of a virtual polyhedron as the core, and establishing a mapping relationship between joint angles and the edge lengths of the virtual polyhedron; S2, constructing an optimization objective function based on the Hadamard product based on the error between the target edge length set and the actual edge length set of the virtual polyhedron; S3, generating an initial set of iteration points covering all quasi-convex regions in the joint space of the polyhedral open-chain robot; S4, solving the gradient of the objective function and iteratively updating the joint angles; S5, setting a convergence threshold and termination condition, performing convergence judgment on the iteration process, and selecting the optimal solution for inverse kinematics; This invention achieves accurate modeling of the inverse kinematics of a tetrahedral mobile robot by constructing an error optimization model based on the edge lengths of a virtual polyhedron and combining Monte Carlo sampling initialization and gradient descent iterative solution.

Methods and apparatuses for capturing and encoding ambisonic audio are described herein. An example ambisonic microphone may comprise a first microphone capsule oriented substantially toward a first vertex of a notional tetrahedron, a second microphone capsule oriented substantially toward a second vertex of the notional tetrahedron, a third microphone capsule oriented substantially toward a third vertex of the notional tetrahedron, and a fourth microphone capsule oriented substantially toward a fourth vertex of the notional tetrahedron.

The application discloses an organ non-rigid deformation processing method and system for laparoscope augmented reality navigation and a medium. The method comprises the following steps: acquiring an organ preoperative surface mesh model and converting the organ preoperative surface mesh model into a solid mesh model containing mesh units; generating an editable cage-shaped framework based on the solid mesh model, and optimizing a framework sparsity factor by using a loss function combining similarity and sparsity; establishing a physical constraint system covering distance, area and volume preservation on line, surface and tetrahedron units of the solid mesh model, and constructing an internal and external structure coupling deformation mechanism; and in response to an interactive displacement instruction for a control vertex of the cage-shaped framework, iteratively solving new positions of each node in the solid model according to a physical constraint relationship. Through cage-shaped framework driving and physical consistency constraint, the application realizes real-time synchronous deformation of internal and external structures of an organ, effectively solves the problem that a model and a real shape are inconsistent in laparoscopic surgery, and significantly improves navigation precision.

An apparatus is disclosed that defines and uses a bounding volume to test the intersection of light rays with a displacement microgrid. The bounding volume is indirectly based on a twisted prism consisting of two triangles and three bilinear facets, which encloses the displacement microgrid. Instead of directly detecting intersections with the bilinear facets, tetrahedrons circumscribed in the bilinear facets are alternatively used. The two bases and three tetrahedrons form fourteen triangles. The apparatus tests potential intersections with the displacement microgrid by testing intersections with any one of these fourteen triangles. Various other methods and systems are also disclosed.

In various examples, a deep three-dimensional (3D) conditional generative model is implemented that can synthesize high-resolution 3D shapes using simple guides, such as coarse voxels, point clouds, etc., by synthesizing implicit and explicit 3D representations into a hybrid 3D representation. The present approach can directly optimize the reconstructed surface, allowing for the synthesis of finer geometric details with fewer artifacts. The systems and methods described herein can use a deformable tetrahedral grid that encodes a discrete signed distance function (SDF) and a differentiable marching tetrahedral layer that converts the implicit SDF representation to an explicit surface mesh representation marching tetrahedra. This combination allows for joint optimization of surface geometry and topology, as well as the generation of a subdivided hierarchy using reconstruction and adversarial losses explicitly defined on the surface mesh.

This invention discloses a method for constructing a 3D tunnel model and simulating fire, comprising: First, randomly generating tunnel parameters such as tunnel alignment, side profile, cross-sectional shape, and total road width. Then, determining the position coordinates of various points along the tunnel's road centerline according to a fixed step size, based on the tunnel alignment and side profile. Next, generating contour curves of the tunnel's inner and outer walls at each position point based on the randomly generated cross-sectional shape and a set tunnel wall thickness. Finally, combining the contour curves, total road width, and random step size, generating tetrahedrons corresponding to each position point and assembling them to form a 3D tunnel model. In this way, diverse 3D tunnel models can be constructed without manual modeling. Furthermore, by combining randomly generated fire source and ventilation parameters, tunnel fire simulation can be performed using fire simulation software to obtain tunnel fire simulation data, thereby enabling the generation of large-scale simulation data required for deep learning model training.

The application discloses a fluorine-containing zirconium phosphate compound, a nonlinear optical crystal thereof and a preparation method and application thereof, and belongs to the technical field of inorganic functional crystal materials. The chemical formula of the fluorine-containing zirconium phosphate compound is ZrPO4F. The nonlinear optical crystal is composed of a [PO4] tetrahedron and a fluorine-containing zirconium coordination polyhedron to form a three-dimensional skeleton structure, zirconium is six-coordinated and forms a zirconium oxygen coordination polyhedron containing F; the nonlinear optical crystal is a non-centrosymmetric crystal; the nonlinear optical crystal is of an orthorhombic system; the space group of the nonlinear optical crystal is Pna 21; the cell parameters of the nonlinear optical crystal are a = 11.6094 (5) Å, b = 6.9038 (3) Å, c = 5.4921 (2) Å, α = β = γ = 90°, Z = 4, and the unit cell volume is V = 440.19 (3) Å 3 . The nonlinear optical crystal has a nonlinear optical effect, a large band gap (deep ultraviolet transparency), a wide transmission range and easy preservation, and is a nonlinear optical crystal material with great potential application value.

Various embodiments disclosed relate to a shaped abrasive particle. The shaped abrasive particle includes at least four major faces and at least six edges joining the four major faces. One of the at least four major faces is a first rake face, a second of the at least four major faces is a second rake face. The first and second rake faces are predominantly joined along only one common edge. A dihedral angle between the first rake face and the second rake face is in a range of from about 71 degrees to about 170 degrees.

The utility model discloses a quick clamping combination tool for axle end base multistation processing, including lathe carousel subassembly, cross tetrahedron structure stand column subassembly, clamping groove positioning subassembly and movable rotary positioning subassembly, cross tetrahedron structure stand column subassembly includes the cross tetrahedron structure main part of the stand column subassembly, and the stand column subassembly includes facade board and the symmetric setting back side board, and both sides of facade board are equipped with at least two pairs of U groove symmetry, and the fixed nut in U groove is used for installing locking groove screw, clamping groove positioning subassembly includes V type positioning block, and the upper end of V type positioning block is equipped with V type gap, and the both sides are provided with a plurality of spring plunger respectively and are used for adjusting the clearance between both ends by abutting the inner side of axle end base, movable rotary positioning subassembly includes vertical quick clamp, and the vertical quick clamp sets up clamp support and is connected in the upper end of stand column subassembly, and the anvil of vertical quick clamp is connected with the preparation movable presser. Can improve the clamping efficiency, guarantee the machining accuracy and reduce the labor intensity.

This disclosure relates generally to CT x-ray imaging systems and methods, and particularly to an inverse geometry with tetrahedron beams. Specifically, a dose efficient and controllable inverse geometry tetrahedron beam CT imaging is disclosed. The disclosed CT geometry includes a linear array of x-ray sources perpendicular to a rotation axis of the CT system and rotates together with a linear detector array extended parallel to the rotation axis. The x-ray emission from each of the sources is collimated into a fan-shaped beams projected to the linear detector array. The intensity of each beam is dynamically adjusted and controlled during the rotation of the source array and the detector array. Such a configuration provides control of x-ray intensity over a selected region of interest in a target object during the rotation even if the region of interest is off from the rotation axis, with efficient dose control.

This invention relates to the field of geophysical exploration technology and discloses a three-dimensional polarizability inversion method based on cross-gradient constraints. The method includes the following steps: acquiring apparent resistivity observation data d_obsr and equivalent apparent resistivity observation data d_obsη; performing hybrid mesh partitioning on the computational domain to generate a hybrid mesh model containing triangular prism elements, tetrahedral elements, and pyramidal elements; and performing three-dimensional resistivity forward modeling based on the hybrid mesh model to obtain the total field potential. This three-dimensional polarizability inversion method based on cross-gradient constraints, by employing a hybrid mesh (combination of triangular prism, tetrahedral, and pyramidal elements) partitioning technique, can accurately fit undulating surfaces, fundamentally eliminating the terrain influence error caused by mesh simplification. Measured data show that the forward modeling response error at steep terrain measurement points can be reduced from 5.1% to 1.5% using traditional methods, effectively suppressing false anomalies and making the anomaly boundary more clearly delineated.

A modified hydrogen type silico-aluminate molecular sieve, characterized in that (1) the A value is 4.0-6.0 and the B value is not less than 1.4, in the formula: the Q4, Q3, Q2, Q1 and Q0 respectively correspond to the SiO4 tetrahedron structure of the molecular sieve MAS NMR 29 The peak area of five distinguishable peaks appearing in the Si spectrum corresponds to the SiO4 tetrahedron structure of the species, and the peaks from high field to low field are in turn corresponding to Si(4Si, 0Al), Si(3Si, 1Al), Si(2Si, 2Al), Si(1Si, 3Al) and Si(0Si, 4Al) resonance peaks; (2) the surface silicon aluminum molar ratio is 0.9-2.0; (3) the bulk silicon aluminum molar ratio is 2.0-4.0.

The present application is suitable for the field of geophysical inversion technology, and provides a non-structure triangular grid gravity inversion method based on equivalent coplanar-function fitting, comprising the following steps: step S1, obtaining the Bouguer gravity anomaly; step S2, carrying out tetrahedron dissection on the underground space according to the terrain data; step S3, calculating the kernel function according to the equivalent principle; step S4, carrying out iterative inversion according to the function fitting method to obtain the density distribution of the underground space. The present application accelerates the kernel function calculation and iterative calculation process by combining the equivalent principle and the function fitting method, effectively improves the calculation efficiency, saves the calculation time, effectively solves the high-efficiency calculation problem of gravity inversion under the non-structure grid dissection of large data in the undulating terrain area, and is suitable for mineral exploration with high resolution in the undulating terrain area and scientific research on large-area deep complex structure.

This provides a method for aligning partially overlapping point clouds based on double coincidence. [Solution] The method involves acquiring the source and target point clouds of an entity object, generating a matching point set using a low-level matching method, then filtering and sampling the matching tetrahedron set using a high-level matching method, and finally obtaining the optimal transformation matrix by progressing from coarse estimation to fine estimation. During alignment, the optimal transformation matrix is ​​used to convert the source point cloud of the target entity object into a target point cloud, completing the alignment of partially overlapping point clouds.

This invention discloses a three-dimensional angle-of-arrival (AOA) positioning method and system based on geometric center intersection positioning. The method first establishes a three-dimensional AOA positioning system model based on geometric center intersection, expressing the azimuth and elevation angles as nonlinear functions related to the target distance. Second, it establishes three-dimensional AOA positioning rules based on the inscribed sphere center. At each measurement node, two planes are extended based on the two angles, and the distance from any point in space to these planes is calculated. Finally, based on the definition of the inscribed sphere of a three-dimensional tetrahedron, the inscribed sphere center of the geometric body enclosed by these geometric planes is obtained as the estimated target position. Simultaneously, based on the radius of the inscribed sphere obtained at the same time, the noise variance of the current angle measurement is calculated. The system includes a system model construction module, a plane extension module, and a target position estimation module. This invention achieves high performance with extremely low complexity, is suitable for three-dimensional AOA positioning scenarios, and has a wide range of applications.