Abstract: A method for manufacturing a core-shell coaxial gallium nitride (GaN) piezoelectric nanogenerator is provided. A mask covering a center part of a gallium nitride wafer is removed. An electrodeless photoelectrochemical etching is performed on the gallium nitride wafer to form a primary GaN nanowire array on a surface of the gallium nitride wafer. A precious metal layer provided on the surface of the gallium nitride wafer is removed and an alumina layer is deposited on the surface of the gallium nitride wafer to cover the primary GaN nanowire array to obtain a core-shell coaxial GaN nanowire array. A first conductive layer is provided on a flexible substrate to which the core-shell coaxial GaN nanowire array is transferred. A second conductive layer is provided at a top end of the core-shell coaxial GaN nanowire array, and is connected to an external circuit to obtain the core-shell coaxial GaN piezoelectric nanogenerator.

Abstract: The present disclosure belongs to the technical field of power batteries, and in particular relates to a phase change composite and a preparation method and use thereof. The phase change composite includes the following components in parts by weight: 50 parts to 70 parts of a phase change material (PCM), 10 parts to 20 parts of a maleic anhydride graft, 1 part to 5 parts of a thermal conductivity enhancer, and 15 parts to 30 parts of a flame retardant; where the flame retardant includes melamine and triphenyl phosphate. The phase change composite has flame retardancy, high latent heat, and great thermal conductivity.

Abstract: A method is disclosed that divide a total frequency band of a communication system into several equally spaced non-overlapping information channels, which are allocated to different users; the information channels are in one-to-one correspondence with the users; user signals from different addresses are distinguished based on frequency, thereby completing the multiple access connection; and duplex communication between two users uses a fundamental frequency and harmonics for information transmission. A process of the information transmission is as follows: different information is first modulated and then is separately loaded on different harmonic components, different information is transmitted through different harmonic components or component combinations so that each pair of information channels can transmit N groups of different information at the same time, and finally the fundamental frequency and harmonic information received by a receiving end is demodulated to obtain all the transmitted information.

Abstract: A reconstruction method for DCSK signals is provided. An information bit sequence to be transmitted is acquired, which is processed by serial-to-parallel conversion. A processed information bit sequence is input into a modulator for modulation to obtain a modulated signal matrix. Cross multiplication is performed between the modulated signal matrix and a chaotic signal to obtain an original information-bearing matrix, which is reconstructed according to a predetermined reconstruction matrix to obtain an information-bearing reconstruction matrix. A transmission symbol is generated according to the information-bearing reconstruction matrix and a reference signal matrix in combination with frame structure information of the transmission symbol, and is sent to a receiving end via a wireless network to demodulate a received signal according to a reconstruction matrix. A reconstruction device for DCSK signals is also provided.

Abstract: A cutting stock method for a rectangular sheet with defects includes: acquiring information of the rectangular defective sheet, including dimension information of the rectangular sheet and target blocks, and location information of the defects; acquiring a cutting position discrete set of the rectangular sheet; cutting the rectangular sheet according to the cutting position discrete set into a plurality of target blocks; calculating a sum of values of the target blocks, and selecting an optimal cutting solution with the largest sum of values; and cutting the rectangular sheet according to the optimal cutting solution.

Abstract: The present disclosure discloses a terahertz detector based on a Schottky contact grating structure. THz response frequency points are adjusted by adjusting parameters (a grating width, a grating length, a grating region area, a grating period, and a grating pattern form) of the Schottky contact grating structure (in the detector design stage, the grating structure parameters can be adjusted according to the actually required detection frequency points (single frequency point or multiple frequency points)), thereby realizing single-frequency detection or realizing that one detector supports the detection of multiple frequency points. The grating is introduced into the Schottky Barrier Diode, so that the grated Schottky contact resonates with the terahertz waves, the plasma resonance effect is enhanced, and the detection sensitivity is further improved.

Abstract: A packing method for a defective sheet based on branch-and-cut algorithm, including: acquiring sheet information, where the sheet information includes size information of the defect sheet, size information of a target block and position information of a defect; based on actual cutting requirements, establishing constraints; and establishing a primal problem model according to the constraints; converting the primal problem model into a relaxed problem model; checking and verifying the obtained solution by x-check method to determine whether the obtained solution meets the constraints of the primal problem model; outputting the optimal solution to obtain an optimal cutting plan that meets the actual cutting requirements; and cutting the defective sheet according to the optimal cutting plan. A system for implement the packing method is also provided.

Abstract: A non-coherent long range (LoRa) communication system based on multiple-input multiple-output (MIMO) technology, including a transmitter and a receiver. The transmitter is configured to transmit signals to the receiver, and the receiver is configured to receive and demodulate the signals. The transmitter includes a bit-symbol converter, a space-time mapper, and a plurality of transmitting antennas. The space-time mapper is configured to select a transmit antenna for the signal in each transmission time slot and transmit a base Chirp signal x0 and the modulating signal xm to the receiver in different time slots. The receiver includes a plurality of receiving antennas. The receiving antenna is configured to preprocess the signal to obtain a first cache matrix and a second cache matrix. After Hadamard product operation is performed on the first and second cache matrixes, operation results of the receiving antennas are accumulated and demodulated to output demodulated information bits.

Abstract: The present application relates to an N×M terahertz detector array imaging system based on a multi-frequency antenna structure, wherein a single-frequency-point terahertz antenna used for receiving terahertz signals in a traditional detector is replaced with a multi-frequency-point terahertz antenna, thereby realizing that one detector supports the detection of multiple arbitrary different frequency points. The traditional detector needs to replace detectors with different frequency points for detection of different frequency points. The present application can design a multi-frequency-point terahertz antenna with arbitrary different frequency points according to actual needs, so that one detector can support the detection of multiple arbitrary different frequency points without the replacement of the terahertz detector, effectively reducing the cost of terahertz detection and imaging.

Abstract: A glucose sensor electrode, a preparation method therefor and the use thereof are provided for the rapid and sensitive detection of glucose. The method involves: (1) performing an alkali heat treatment to form a nanoneedle-structured titanium dioxide on the surface of a titanium electrode; (2) forming micro-region grooves on a nanoneedle-structured titanium dioxide film layer to obtain a nanoneedle-structured titanium dioxide having a micropattern; (3) depositing a chlorine-doped polypyrrole in the grooves by using chronopotentiometry; (4) forming a nanocone-structured citric-acid-doped polypyrrole on the chlorine-doped polypyrrole by using chronopotentiometry; and (5) grafting an enzyme capable of detecting glucose to obtain the glucose sensor electrode. This simple and stable process is low in cost, efficiently grafts the enzyme capable of detecting glucose on the surface of the electrode, and provides a stable electrode with higher reliability for detecting glucose.

Abstract: A laser cutting method for irregular parts based on machine vision includes: (A) obtaining and numbering vertices of all parts on the layout diagram; (B) planning a part vertex set and an empty cutting path vertex set; (C) obtaining a shortest empty cutting path and the empty cutting path vertex set with the shortest empty cutting path; (D) cutting the parts one by one according to an order obtained by the CPLEX algorithm. This application further provides a laser cutting system.

Abstract: A method of fabricating a magnetically-controlled graphene-based micro-/nano-motor includes: (a) mixing FeCl3 crystal powder with deionized water to obtain a FeCl3 solution; (b) completely immersing a carbon-based microsphere in the FeCl3 solution; transferring the carbon-based microsphere from the FeCl3 solution followed by heating to allow crystallization of FeCl3 on the surface of the carbon-based microsphere to obtain a FeCl3-carbon-based microsphere; (c) heating the FeCl3-carbon-based microsphere in a vacuum chamber until there is no moisture in the vacuum chamber; continuously removing gas in the vacuum chamber and introducing oxygen; and treating the FeCl3-carbon-based microsphere with a laser in an oxygen-enriched environment to obtain the magnetically controlled graphene-based micro-/nano-motor. A magnetically-controlled graphene-based micro-/nano-motor is further provided.

Abstract: A structured light 3D measurement device and method based on defocus-degree-based unwrapping. Binary fringes varying in fringe width are projected onto an object, and a corresponding fringe image is collected by a camera, and then subjected to phase demodulation to calculate a wrapped phase. The defocus degree is calculated according to modulation degrees of the binary fringes. The defocus degree is plugged into the defocusing phase function to obtain a normalized reference phase. The wrapped phase is subjected to phase unwrapping based on the normalized reference phase to obtain an absolute phase to reconstruct a 3D point cloud.

Abstract: This disclosure relates to optical three-dimensional (3D) measurement, and more particularly to a large-depth-range 3D measurement method, system, and device based on phase fusion. Sinusoidal fringes corresponding to multiple high-frequency binary fringe patterns varying in stripe width, a middle-frequency binary fringe pattern, and a low-frequency binary fringe pattern are formed and then projected onto a to-be-measured object. After modulated by height of the object, the sinusoidal fringes are collected, and wrapped phases of the collected sinusoidal fringes are calculated to determine absolute phases of high-frequency sinusoidal fringes. Phase errors of a high-frequency sinusoidal fringe under different fringe widths are calculated according to the defocusing degree. An optimal absolute phase is selected based on the phase errors for the large-depth range 3D measurement.

Abstract: A real-time pose measurement method of a planar coding target for a vision system. The planar coding target includes a plurality of coding elements, a coding block, a coding template, a minimum identification unit pattern and a coding pattern. Each coding element has a unique coding value, and serial numbers of the coding elements are different from each other. The coding block includes four coding elements that are distributed in the same rectangle ABCD and do not overlap with each other. A center of the coding block is an intersection point O of two diagonals of the rectangle ABCD. A coding value of the coding block is associated with coding values of the four coding elements contained therein.

Abstract: A dynamic optimization method for procurement specifications of BEF raw materials includes: obtaining finished product data; obtaining an initial feasible raw material size set; mapping the initial feasible raw material size set in length and width directions to obtain a complete feasible raw material size set; filtering an unreasonable raw material size out of the complete feasible raw material size set to obtain a final feasible raw material size set; and determining whether a scale of the final feasible raw material size set is larger than a threshold, if not, building and solving an integer programming model, and outputting results; and if yes, batchwise processing the final feasible raw material size set to obtain multiple subsets, and building an integer programming model for each subset, and solving the integer programming model, and outputting results. A dynamic optimization system of BEF is further provided.

Abstract: A pilot protection method includes: obtaining time-domain signals data of target element at a preset sampling frequency; fusing time-domain signals data of multiple first sampling periods to obtain first time-domain signals combination data; based on a machine learning model, determining whether a fault occurs in target element according to the first time-domain signals combination data; when it is determined that a fault occurs in target element according to the first time-domain signals combination data, based on the machine learning model, determining whether a fault occurs in target element in the second sampling period according to the second time-domain signals combination data. The second sampling period is the sampling period after determining a fault occurs; when it is determined that the same type of fault occurs in target element in multiple consecutive second sampling periods, the pilot protection system is controlled to perform the protection action on the target element.

Abstract: Disclosed are a background filtering method and a system based on a roadside solid-state lidar, whereby a spatial dividing method of solid-state lidar based on channel scanning angle is designed, single-channel point cloud is extracted, point cloud of each channel of all background data frames are fused and superimposed, each background space unit and non-background space unit based on channel scanning space are identified based on a given threshold; then real-time data frames are subjected to background difference based on channels to obtain the single-channel road user information data frames; the background filtering is achieved by splicing single-channel road user information data frames into a complete road user information data frame.

Abstract: A differential chaos shift keying communication method based on hybrid index, including: modulating a transmitted signal based on the hybrid index; and demodulating a received signal based on the hybrid index. The hybrid index is a hybrid index bit, which includes a carrier index bit and a carrier number index bit. This application also provides a system for implementing the differential chaos shift keying communication method, which includes a transmitter and a receiver.

Abstract: A novel high-precision rigid-flexible coupling rotating platform includes a foundation, a rigid bearing, a bearing sleeve, a core rotating platform, a rotating driver and a coder; the bearing sleeve is fixed on the foundation; the rigid bearing is in rotatable drive connection with the core rotating platform, and connected with the foundation through the bearing sleeve; an upper surface of the core rotating platform is provided with a plurality of groups of flexible hinges; when the rotating driver applies a driving force to rotate the core rotating platform, the driving force elastically deforms the flexible hinge rings. The flexible hinges are used and disposed on the upper surface of the core rotating platform; without disassembling the whole rotating platform, a corresponding group of flexible hinges can be changed but an assembling relationship between other groups of flexible hinges cannot be broken.