10 results about "Primitive cell" patented technology

The invention belongs to the technical field of photonic crystals, and particularly relates to a photonic lattice capable of cutting boundaries in various modes and a method for generating a boundary state. In order to provide crystal lattices with a larger existence range, the evanescent coupling straight waveguides comprise a plurality of uniformly distributed crystal lattice points, the evanescent coupling straight waveguides are arranged on the crystal lattice points, every three crystal lattice points form a primitive cell, and the three crystal lattice points in each primitive cell form an equilateral triangle. The interfaces on the two sides of the evanescent coupling straight waveguide are arranged to be one or two of an alpha-zigzag shape, a beta-zigzag shape and a beam shape. According to the method, construction is simple, various boundaries can be cut, and two different types of boundary states are supported.

The invention discloses an acoustic topological acoustic fiber device based on a microstructure. The acoustic topological acoustic fiber device comprises a plurality of primitive cells arrayed in the Z direction. Each primitive cell is of a multi-layer honeycomb lattice structure and comprises an A-layer assembly, a middle-layer assembly, a B-layer assembly and a middle-layer assembly which are sequentially stacked from top to bottom. Pi phase difference delay exists between the A-layer assembly and the B-layer assembly. The middle layer assembly is constructed to be of an integral structure formed by connecting a plurality of coupling units. Seen from an X-Y plane, the primitive cell is constructed to be composed of a plurality of non-periodic structural units; rotation parameters are introduced into the structural units, so that the centers of the primitive cells have vortex centers, and the vortex centers are connected in the Z direction to form vortex lines. The acoustic topological acoustic fiber device disclosed by the invention can transmit in the center of the device in a defect immune manner without a magnetic field.

The invention discloses a device capable of localizing a surface acoustic wave center. The device comprises a device body and hard boundaries arranged on the upper surface and the lower surface of the device body. The device body comprises a plurality of primitive cells arrayed in the Z direction and an A-layer assembly arranged on the lower surface of the bottommost primitive cell. Each primitive cell comprises a B-A coupling layer assembly, a B-layer assembly, an A-B coupling layer assembly and an A-layer assembly which are sequentially stacked from bottom to top; pi phase difference delay exists between the A-layer assembly and the B-layer assembly. The primitive cell is constructed to be composed of a plurality of non-periodic structural units; the structural unit comprises a B-A coupling unit and a structure B which are arranged from bottom to top, the coupling strength of the A-B coupling unit and the coupling strength of the structure A are different, and the coupling strength of the A-B coupling unit and the coupling strength of the B-A coupling unit are different; rotation parameters are introduced into an X-Y plane in a three-dimensional space where the device is located, so that the primitive cell center has a vortex center, and the period of the primitive cell in the Z direction is of a limited size. Through the device, a zero-dimensional topological angular state can be formed, and surface acoustic waves are localized in the center of the top surface of the device.

The invention belongs to the technical field of multiferroic materials, and relates to a design method of a multiferroic body based on a vanadium-doped two-dimensional ferroelectric and the multiferroic body. Performing cell expansion on the single-layer NbOI2 primitive cell in different directions to obtain supercells with different sizes; the method comprises the following steps: doping supercells with different sizes by taking vanadium as a doping element to obtain a doping configuration of each supercell under different doping concentrations; taking the doping configuration with the lowest total energy of the ferromagnetic state and the antiferromagnetic state under each doping concentration as the ground state configuration of the doping concentration; calculating band gaps Eg of ground state configurations with different doping concentrations and spontaneous ferroelectric polarization intensity along a b axis, drawing a double-Y-axis curve graph by taking the doping concentrations as abscissas and the spontaneous ferroelectric polarization intensity and the band gaps Eg as ordinates, and dividing a multiferroic phase region and a magnetic semimetal phase region to obtain a doping concentration-physical property evolution phase diagram; and obtaining a corresponding doping concentration value range when the ground state configuration has a multiferroic phase with ferroelectricity and antiferromagnetism so as to design a multiferroic body.

Any primitive cells or blocks can be represented physically by a Barycenter compact model (or Barycenter model), and any black box model can also be physically represented by a Barycenter compact model physically. A boundary condition between blocks is formulated by the Barycenter compact model. Boundary condition problems between blocks can be limited within two levels only if using the Barycenter compact model.

The application discloses a single crystal growth method of Bi-O-Se-Cl four-component semiconductor material. The chemical formula of the Bi-O-Se-Cl four-component semiconductor material is Bi 10 O 12 SeCl4, each unit cell of the crystal contains 98 atoms, has a layered structure with two layers of [Bi 12 O 12 Se2Cl], two layers of [Bi6O 10 ] and four layers of [3Cl] alternately stacked along the c-axis. The growth method is as follows: bismuth powder and selenium powder are ground and mixed, and then a solid phase reaction is caused to obtain bismuth selenide; bismuth oxide, bismuth chloride and bismuth selenide are ground and mixed to obtain mixed powder 2, which is placed at the bottom of a quartz tube, vacuumized and sealed; the sealed quartz tube is horizontally placed in a two-zone furnace, and gas phase transportation is started; the hot end and the cold end of the two-zone furnace are respectively subjected to gradient heating and heat preservation, and after the end, the two-zone furnace is cooled, and thus Bi 10 O 12 SeCl4 crystals are obtained. The Bi 10 O 12 SeCl4 crystal has a complex layered structure and is a candidate material with intrinsic low thermal conductivity, and the growth method is simple and reliable.

The application belongs to the technical field of multiferroic materials, and relates to a design method of a multiferroic material based on a vanadium-doped two-dimensional ferroelectric body and the multiferroic material. Single-layer NbOI2 primitive cells are expanded in different directions to obtain supercells of different sizes. Vanadium is used as a doping element to dope the supercells of different sizes, and the doping configurations of each supercell under different doping concentrations are obtained. The doping configuration with the lowest total energy of the ferromagnetic state and the antiferromagnetic state under each doping concentration is used as the ground state configuration of the doping concentration. The band gap Eg and the spontaneous ferroelectric polarization intensity along the b-axis of the ground state configuration under different doping concentrations are calculated. A double-Y-axis curve graph is drawn with the doping concentration as the horizontal coordinate and the spontaneous ferroelectric polarization intensity and the band gap Eg as the vertical coordinate, and the multiferroic phase region and the magnetic semimetal phase region are divided. The doping concentration-physical property evolution phase diagram is obtained, so that the corresponding doping concentration value range of the ground state configuration with the multiferroic phase of ferroelectricity and antiferromagnetism is obtained to design the multiferroic material.

A technique generates a hierarchical three-dimensional structure or volume mesh and uses intelligent compaction using a Barycenter compact model. Any primitive cells or blocks can be represented physically by a Barycenter compact model (or Barycenter model), and any black box model can also be physically represented by a Barycenter compact model physically. A boundary condition between blocks is formulated by the Barycenter compact model. Boundary condition problems between blocks can be limited within two levels only if using the Barycenter compact model. A technique generates a hierarchical three-dimensional volume mesh and uses intelligent compaction using a Barycenter compact model.

This application relates to the field of acoustics, and in particular to a method for realizing a three-dimensional phononic crystal structure, an acoustic supercell, and an acoustic device. The phononic crystal structure is composed of multiple stacked unit cells; each unit cell includes several resonant cavities and acoustic coupling channels connecting the resonant cavities; the layers are connected by interlayer acoustic coupling channels; the geometric parameters of the resonant cavities and acoustic coupling channels are configured to satisfy a tightly bound model with chiral symmetry, such that the phononic crystal structure forms nodal loops in three-dimensional momentum space and supports higher-order topological hinge states at the rigid boundary edges of the phononic crystal structure. This invention can achieve stable higher-order topological hinge states while maintaining the characteristics of nodal loops, and has the advantages of simple structure and ease of fabrication.

A technique generates a hierarchical three-dimensional structure or volume mesh and uses intelligent compaction using a Barycenter compact model. Any primitive cells or blocks can be represented physically by a Barycenter compact model (or Barycenter model), and any black box model can also be physically represented by a Barycenter compact model physically. A boundary condition between blocks is formulated by the Barycenter compact model. Boundary condition problems between blocks can be limited within two levels only if using the Barycenter compact model. A technique generates a hierarchical three-dimensional volume mesh and uses intelligent compaction using a Barycenter compact model.