55results about How to "Periodic" patented technology

The invention discloses a frame synchronous detection method based on a zero correlation zone (ZCZ) sequence, which is used in a wireless communication system. The frame synchronous detection method comprises the following steps of: firstly, receiving the sequence, and carrying out cross-correlation operation with a local ZCZ sequence; secondly, carrying out conjugate point operation between a front symbol block and a rear symbol block on a cross-correlation operation result; and finally, carrying out a real-part maximum value of each symbol block with a threshold value, and judging whether a frame is coming or not. In order to make the maximum value more apparent, the conjugate point operation between the front symbol block and the rear symbol block on the cross-correlation operation is carried out; and if peak detection is required to be more apparent, the conjugate point operation between the front symbol block and the rear symbol block can be carried out for more times. Compared with the traditional frame detection method, the method is easy to operate and implement, and whether the frame is coming or not can be accurately judged. The method can be applicable to time synchronization, and an initial point of a signal is determined by finding the position of a negative pulse.

The invention provides a telecom user loss prediction method and device based on user internet behaviours. The method comprises the steps of: obtaining at least one internet behaviour data of a targetuser; evaluating the internet behaviour data, and determining an evaluation parameter corresponding to the internet behaviour of the target user; and, on the basis of the evaluation parameter, predicting whether the target user is a potential loss user or not, and predicting the loss probability of the target user. According to the telecom user loss prediction method and device based on the userinternet behaviours provided by the invention, on the basis of internet behaviours of users, subjective feelings and wishes of the users are comprehensively considered based on the statistics; therefore, potential loss users can be predicted in advance; furthermore, a user loss reason can be evaluated completely and accurately; the result is true and reliable; simultaneously, the user loss has periodicity; the potential loss users are predicted in advance; therefore, the users can be discovered in time, and retained by adoption of a corresponding marketing method; the pertinence is high; and the success rate is high.

The embodiment of the invention discloses an attitude control method, device and system for a satellite platform with a rotating load. The attitude control method of the satellite platform includes: measuring an actual attitude parameter of the satellite platform; comparing the actual attitude parameter and a target attitude parameter, and determining an attitude deviation; generating a first control instruction based on the attitude deviation; determining a learning period parameter of a repeating controller of the satellite platform according to a motion law parameter of the rotating load, wherein the repeating controller generates a second control instruction according to the learning period parameter and the first control instruction; and controlling the attitude of the satellite platform by using the second control instruction.

The invention discloses a polar orbit constellation GEO interference avoidance method based on polar orbit satellite attitude bias. Constellation coverage continuity is not considered in a current polar orbit constellation GEO interference avoidance method. In order to solve the problems that the polar orbit constellation service is possibly interrupted, the frequency interference avoidance of theGEO satellite is realized through the attitude continuous bias of the polar orbit constellation satellite, and meanwhile, the polar orbit constellation coverage is continuous and the coverage overlapping area margin is maximum through the optimization of the satellite attitude bias rule, so that the polar orbit constellation coverage continuity is ensured.

The present invention relates to preparation process of periodical nanometer titania line, is especially template process of preparing periodical nanometer titania line, and belongs to the field of nanometer material preparing technology. The present invention prepares periodical nanometer titania line by using alumina with periodical high ordered micropore array as template and through a sol-gel process. The present invention is superior to background technology in that the template process can obtain periodical nanometer titania line product with effectively controlled periodical distribution and size of nanometer titania lines, is simple, feasible, low in cost and pollution-free.

A tunable phase-shift fiber bragg grating relates to a phase-shift fiber bragg grating, in particular to a phase-shift bragg grating with a transmission spectrum with the tunable characteristic, which is based on the fiber bragg grating fabry perot structure. The invention provides a tunable phase-shift fiber bragg grating with fast tuning speed, simple structure, high stability and low cost. The grating is provided with two segments of fiver bragg gratings; a sleeve tube the inner diameter of which is matched with the outer diameter of the fiber bragg grating is inserted into the two segments of the fiber bragg gratings; the gap between the two segments of the fiber bragg gratings is filled with index matched liquid; a gap length adjusting mechanism is arranged in the gap between the two segments of the fiber bragg gratings.

The invention discloses an air-cooled intercooler which comprises a core. The core comprises an air inlet chamber, an air outlet chamber, a radiating tube and a radiating fin, two ends of the radiating tube are respectively communicated with the air inlet chamber and the air outlet chamber, and a spoiler is arranged in the radiating tube. An air inlet and an air outlet are respectively connected onto the air inlet chamber and the air outlet chamber, the spoiler is of deoxyribose nucleic acid (DNA) duplex structure, and the spoiler is formed by two frameworks of the duplex structure and a bond-shaped fin connected between the two frameworks. The air-cooled intercooler is provided with the spoiler of the DNA duplex structure and has the advantages of good heat transfer effects and small flow resistance.

The invention discloses a channel estimation method for single carrier frequency domain equalization under a low energy dispersion multipath channel. A problem of channel estimation performance loss of an existing single carrier equalization system under a low energy dispersion multipath environment can be improved effectively by using the channel estimation method disclosed by the invention. Segmentation is carried out through setting a value of an approximate signal to noise ratio, different numbers of useful signal paths and different threshold values are selected in different signal to noise ratio intervals, and then time domain noise reduction processing of channel estimation is carried out. The channel estimation method disclosed by the invention is not only applicable to extracting the useful signal paths accurately in a high signal to noise ratio environment. In addition, when most of the useful signal paths are possibly submerged in noises and cannot be distinguished in a low energy multipath channel environment, the low energy multipath channel environment is divided into a high signal to noise ratio interval, a middle signal to noise ratio interval and a low signal to noise ratio interval by adopting the method, the useful signal paths can also be extracted accurately, and the performance of channel estimation is improved.

The invention discloses an ultrasonic roadway surface convergence analyzer. The ultrasonic roadway surface convergence analyzer comprises an installing pole, an instrument cabin, a left ultrasonic transceiving transducer, a right ultrasonic transceiving transducer, a lower ultrasonic transceiving transducer and other parts. The analyzer is fixed to a top plate and a bottom plate of a mine roadway or the two sides of the mine roadway through the installation pole. After initialization, the shape and dimensions of the initial section of the mine roadway are recorded, so that an initial image of the section of the roadway is obtained; after the analyzer enters a normal working state, the left ultrasonic transceiving transducer, the right ultrasonic transceiving transducer and the lower ultrasonic transceiving transducer are started according to set time, ultrasonic signals are emitted to the top plate, the bottom plate and the two sides of the roadway and are collected, and the collected ultrasonic composite echo signals are processed through a processor, so that a composite image of the section of the roadway is obtained, wherein compared with the initial image, the deformation and convergence amount of the top plate, the bottom plate and the two sides of the roadway are obtained. The ultrasonic roadway surface convergence analyzer is easy to install, stable and reliable in measurement and capable of achieving non-contact online monitoring of the convergence amount of the whole section of the top plate, the bottom plate and the two sides of the mine roadway, thereby providing online monitoring data of the convergence amount of the whole section for the special project of the mine roadway surface convergence amount.

The invention discloses a length measuring and tracing method using a graphene bond length as a measuring reference. The graphene bond length is used as a length measuring and tracing reference, length measuring and tracing are carried out on an object to be detected by the number of detected graphene bond lengths, and sub-nanometer grade precision length measuring and tracing are realized. Ultra-precision synchronous motion control connection is carried out on the object to be detected and a graphene reference sample bearing table, the number of the graphene bond lengths is scanned to represent the motion length of the graphene reference sample bearing table, and the motion of the graphene reference sample bearing table is detected in real time, so that the sub-nanometer grade precision length measuring is carried out on the object to be detected, and sub-nanometer grade precision length measuring and tracing are realized. As graphene lattices are used as the length measuring and tracing reference, the length measuring and tracing method has the characteristics of high stability, high measuring precision capable of reaching a sub-nanometer grade, simpleness, reliability and the like and has wide application prospects in the field of ultra-precision measuring and tracing.

Interactive digit information transmission characterizes up / down stream signals are in the synchronous step structure. Down-stream signals modulated by TDS-OFDM in down-stream channel in which its frame is PN synchronous signals or mixed synchronous signal frame and in up-line channels, up-line signals modulated by multi-user by burst TDMA, in which its frame synchronous code is PN in 6 step m sequence. The up-line signal frame is made up of multi-user signals shared by multiple user composed of cut-in request and data signals, numbered according to the signal frame structure. The up-line channel cut-in is controlled by the down-stream channel after synchronization via random synchronous cut-in code. Up-link / down stream signals frame structures are synchronized with natural time to support bipolar transmission.

The invention discloses a permanent magnet spherical motor point-to-point motion track planning method based on a sine acceleration function and application thereof. The method is characterized in that a permanent magnet spherical motor rotor is regarded as a research object, firstly a Euler rotation angle or coordinates of two points are given, and the Euler rotation angle is inversely solved by adopting a method of reversely solving the Euler rotation angle according to the coordinates of the two points; then, an expression of the sine acceleration function is solved according to the operating time and initial conditions, and finally a final control torque is obtained according to a rotor dynamics equation. By the adoption of the method, permanent magnet spherical motor point-to-point motion track planning is achieved, the method is applied to complicated and continuous track planning, the adverse influence of input signal impact, non-continuous change and other factors on a control object can be effectively reduced, and accordingly the control accuracy of a control system and the stability of motor operation are improved.

In the position control system, multiple feedbacks such as displacement and speed are used to improve control accuracy. The grating has the advantages of precision, large range, and low cost as displacement feedback. This paper proposes the use of wavelet transform to realize the dual-parameter simultaneous extraction of the displacement and velocity of grating Moiré fringes. The scale factor corresponds to the velocity, the translation factor corresponds to the displacement, and the modulation changes The traditional grating Moiré fringe only measures single parameter of displacement and multi-parameter sensor realizes multi-parameter feedback, which is of great significance for improving positioning accuracy and simplifying the structure of the positioning system.

The invention provides an image forming apparatus capable of easily eliminating the image unevenness based on the speed change generated by a transfer roller. An image forming apparatus including a latent image bearing drum on which a latent image is formed, an exposure unit that exposes the latent image bearing drum, a developer unit that develops the latent image formed on the latent image bearing drum, a transfer medium onto which the image developed by the developer unit is transferred, and a transfer roller that transfers the image from the transfer medium to the transfer material, the transfer roller having a concaved portion extending in the axial direction and a support portion disposed on the outer circumference of the roller that supports the transfer material, where the outer circumference of the transfer roller being an integral multiple or an approximate integral multiple of the circumference of the latent image bearing drum.

The invention discloses a video synchronous sending method supporting high-resolution LED ball screen display, which belongs to the technical field of video synchronous processing, and is characterized in that it comprises the following steps: a. Divide any single-channel 4K high-resolution video frame into N The data of each part; b, for the video data of each part, adopt the interval N row buffering mode to carry out data buffering, the address block is stored sequentially with N as a group of video signals; c, take out the video data from data buffering group as Unit, 2160 / N rows of data per channel are sent to N Gigabit Ethernet ports in parallel for sending until all groups are sent. For a single channel, the present invention can split a complete 4K high-resolution video frame into multiple Ethernet channels for transmission separately, and can ensure the synchronous transmission of 4K high-resolution video frames inside the channel, thereby supporting 4K high-resolution High resolution LED ball screen display.

The invention discloses a frequency hopping signal feature extraction and parameter estimation method, which overcomes the problems of mutual restriction of time and frequency resolution, existence of cross terms and TT transform being sensitive to noise in the prior art. The steps are: 1. Frequency hopping signal sampling; 2. Make smooth pseudo Wigner time-frequency transform; 3. Make TT transform based on SPWVD transform; 4. Draw SPWVD‑TT transform diagram; 6. Find the upper envelope curve and remove the DC component; 7. Estimate the frequency hopping period: perform Fourier transform on the upper envelope curve after removing the DC component, and the frequency corresponding to the maximum amplitude value in the obtained amplitude-frequency diagram is is the estimated value of the frequency hopping rate, and the reciprocal of the frequency hopping rate is the estimated value of the frequency hopping period; 8. Estimated frequency hopping time: pass the remaining peak time points t 1 ,t 2 ,...,t k‑1 Estimate the frequency hopping moment; reduce the error by the cumulative average method, and the initial frequency hopping moment is estimated as

The invention discloses a precise mold of vehicle accumulator shell injection molding parts. The precise mold comprises a front mold and a back mold; a front mold core is fixed on an upper template; a back mold core is fixed on the upper template, and is opposite to the front mold core; the front mold core and the back mold core are closed to form a product mold cavity; a core pulling slide block is arranged at the side part of the mold cavity, and is embedded between the front mold core and the back mold core; slide blocks are arranged at two side parts of the back mold core; the core pulling slide block is connected to the slide blocks; the two slide blocks are guided to slide through two inclined guide columns relatively independently arranged; the inclined guide columns are fixed at two side parts of the front mold core, and the lower end parts are inserted in the slide blocks; the lower side of a runner is communicated with the mold cavity; and a return device is arranged between the back mold core and the slide blocks. The precise mold of the vehicle accumulator shell injection molding parts improves the product performance of the injection molding parts, is short in molding period and high in production efficiency, is low in wear of an accumulator mold by a flux, and can mold the injection molding parts with complex shapes, clear surface patterns and marks and high size precision in large batches.