71 results about "Propagation attenuation" patented technology

The invention discloses a double-end partial discharging positioning method of a long-distance cable based on correction pulses. The correction pulses are used as triggering signals of a double-end partial discharge detector, and the problem that partial discharge of the long-distance cable is attenuated greatly and positioning is hard in single-end partial discharge positioning is solved. In addition, the double-end partial discharging positioning method replaces a method in which GPS synchronous time service is used for positioning, is simpler and more practical, and can be used to simplify equipment and reduce equipment cost. According to the double-end partial discharging positioning method, two partial discharge collectors are used, namely a host collector and a slavery collector, the host collector is installed at the voltage application end of the cable, and the slavery collector is installed at the opposite end of the cable. The two partial discharge collectors use the input correction pulses as the triggering signals. According to the method, errors caused by spreading attenuation of correction signals in the cable are taken into consideration and corrected, and a good positioning effect can be achieved.

The present invention provides a wireless communication system and a terminal. A base station includes means that notifies terminals of an intensity of a received interference power. The terminal includes means that controls a transmission power for transmitting data to the base station, which is one of base stations and to which data is to be transmitted, by referencing an intensity of interference power (OSI) notified from base stations to which data is not to be transmitted. The means that controls a transmission power calculates a decision value for increasing/decreasing the transmission power, wherein the decision value is variable according to the current transmission power of the terminal and propagation attenuations between the terminal and the base stations to which data is not to be transmitted, and variably controls the amount of transmission power increase/decrease according to the decision value for increasing/decreasing a transmission power.

The invention belongs to the field of coal mining, and provides a face-contacted block beam structure compound remnant area upward mining feasibility determination method. The method comprises the steps of S1, judging an upper portion remnant coal position, and if the upper portion remnant coal position is located above a caving zone of lower coal layer mining, conducting S2, otherwise judging theposition not workable; S2, obtaining the rock stratum composition, rock stratum structure and rock stratum physical and mechanics parameters of a remnant coal mining area through drilling; S3, determining the position of a control rock stratum; S4, calculating the disturbance load of the breaking span and bearing pressure of the control rock stratum after propagation attenuation on a face-contacted block body beam semiarch rock stratum structure of a bottom plate; S5, analyzing whether or not revolution, deformation and unstability occur to the face-contacted block body beam semiarch rock stratum structure of the bottom plate under the effect of the disturbance load, and if not, judging that the area is workable. According to the face-contacted block beam structure compound remnant area upward mining feasibility determination method, the workability judgment accuracy degree and mining safety are improved, the method is applicable to the hard control rock stratum with fracture development, and the condition that the face-contacted block body beam semiarch rock stratum structure is formed.

The invention belongs to the technical field of electronic and scientific application, and discloses a large-volume chaff cloud electromagnetic scattering measurement method based on a partition vector transport theory. The large-volume chaff cloud electromagnetic scattering measurement method includes the steps: calculating the distribution of chaff clouds in wake flow in combination with an aerodynamic theory; based on the chaff cloud space distribution model, using a K-means algorithm to carry out rapid partitioning processing on the chaff cloud space distribution model, and using a linearmoment method to calculate an electromagnetic propagation attenuation coefficient in each subarea; based on the partition data and the obtained intra-area propagation attenuation coefficient, establishing a vector transport equation in the whole space area occupied by the chaff cloud, solving the vector transport equation by using a Monte Carlo method, and solving a statistical solution of the vector transport equation by using the emitting, transporting, colliding, tracking and receiving processes of the virtual photons; and based on a solving result of the vector transport equation, obtaining scattering HH, HV, VV and VH polarization modes through Stokes vector transformation processing. According to the large-volume chaff cloud electromagnetic scattering measurement method the problem of low calculation efficiency of the scattering cross section of the large-volume chaff cloud radar in the prior art is solved, and meanwhile, the problem of calculation of the scattering cross sectionof the chaff cloud radar in the aircraft wake flow is effectively solved.

The invention discloses an ascending mining feasibility determination method for a tool post residual mining area considering static disturbance loading and unloading and belongs to the field of coalmining technology. According to the method, first, distribution positions of the tool post residual mining area and leftover coal seams are ascertained, the composition, structure and physical mechanical parameters of rock strata between the coal seams are acquired, and the rock strata between the coal seams are subjected to unified division and numbering from bottom to top; second, the position of a control rock stratum is determined, and disturbance loads acting on leftover coal posts and the control rock stratum in the tool post residual mining area after bearing pressure is subjected to propagation attenuation are calculated respectively; and last, considering the action of static disturbance loading and unloading, the stability of the leftover coal posts and the control rock stratum in the tool post residual mining area is analyzed, and an ascending mining feasibility determination result of the tool post residual mining area is obtained. Through the method, the situation that anempirical method has a large error is avoided, a theoretical basis is provided for ascending residual coal safe mining in the tool post residual mining area, the recovery rate of upper coal resourcesin the tool post residual mining area is increased, and the service life of a mine is effectively prolonged.

The invention discloses an in-formation radar far field prediction method taking regard of near sea surface atmosphere environment influence. The method comprises steps that (1), according to the in-formation radiation source radar mounting height position, radar initial field distribution is calculated; (2), according to radar signal characteristics, a near sea surface atmosphere refractivity model is established; (3), according to the relative position of a radiation source radar and an observation point and the atmosphere refractivity model on a formation radar propagation path, a formation radar electromagnetic signal forward propagation model is established, and propagation attenuation factors taking regard of near sea surface atmosphere influence are calculated through utilizing a two-dimensional parabola algorithm; and (4), lastly, in combination with shipborne radar directional diagram characteristics, an electromagnetic environment of the in-formation far field is solved, and prediction field intensity of the observation point is calculated. The method is advantaged in that radar far field intensity at the observation point is predicted through establishing the electromagnetic signal forward propagation model taking regard of influence of near sea level rough sea surface reflection and near sea surface atmosphere environment parameters, environment parameters are provided for formation electromagnetic compatibility analysis, and the method is applicable to electromagnetic interference analysis.

The present invention provides a sound source location method and system. The method comprises the steps of: controlling sound source play test audio signals to be located, and recoding starting playtime of the test audio signals; collecting audio signals at preset at least two reference points, respectively identifying the test audio signals in the collected audio signals collected at each reference point according to feature information of the test audio signals, and determining arrival time of the test audio signals arriving at each reference point; calculating the relative distance between a sound source and each reference point according to time difference between the starting play time of the test audio signals and the arrival time of the test audio signals arriving at each reference point, and determining the position of the sound source according to the relative distance of the sound source and each reference point. The method and the system overcome the problem that a traditional technology employs a propagation attenuation coefficient to determine the position of the sound source to cause inaccurate sound source location, achieve the technical effect of accurately locating the sound source and provide quality guarantee for audio sound field restoring by employing the sound source.

The invention provides a sound source locating method and a sound source locating system, and the method comprises the following steps: controlling a to-be-located sound source play test audio signal,and recording start play time of the test audio signal; acquiring an audio signal at a preset reference point, identifying the test audio signal from the audio signal according to feature informationof the test audio signal, and determining arrival time of the test audio signal; according to difference between start play time and arrival time of the test audio signal, calculating relative distance between the sound source and the reference point, and determining a position of the sound source according to the relative distance and the position information of the reference point. The method and the system provided by the invention overcome a problem of inaccuracy of sound source locating caused by judging the position of the sound source through a propagation attenuation coefficient in the conventional technologies, achieve the technical effect of accurately locating the sound source and provide quality guarantee for performing sound field restoration through the sound source.

The invention provides an interval confidence evaluation-based roadside node positioning method. The method comprises steps: a roadside node initializes parameters and variables, and according to the self communication radius R and road conditions, adjacent roads are divided into N intervals, and an energy attenuation list P is built for each interval; according to received vehicle release information and signals, the roadside node carries out interval energy attenuation statistics; statistics is carried out on the energy attenuation list of each interval, and a confidence value of the interval is obtained; a confidence interval is selected for positioning; and readjustment is carried out according to the confidence value of the interval. Through dividing communication areas, statistics and analysis are carried out on position information and received signals of a large amount of vehicles, a vehicle coordinate interval with high confidence and interval signal propagation attenuation are selected for positioning calculation, position coordinates of the node is estimated, and an important role is played in application development of aspects such as positioning of a vehicle ad hoc network in a complicated environment and the safety.

The invention discloses a multiband ultra-wideband imaging processing method for near-field measurement of an MIMO radar. The method comprises the main steps that a filtering-inverse projection (MIMO-FBP) algorithm suitable for near-field measurement of the MIMO (multiple-input-multiple-output) radar is used to carry out image reconstruction on multiband imaging data of the MIMO radar, and channelequalization, directional diagram correction, propagation attenuation compensation and spherical wavefront correction are completed automatically in each band to obtain low-resolution complex imagesin the different bands; 2D fast Fourier transform (2D-FFT) is carried out to transform the complex images in the different bands to corresponding data domains, re-sampling is carried out along a sector ring, and sector ring domain data corresponding to the images in the different bands is obtained; and the multiband sector ring domain imaging data is fused in a proper manner to obtain full waveband MIMO ultra-wideband imaging data; and a traditional FBP imaging algorithm is used to carry out image reconstruction on the fused full waveband data. Thus, a full waveband high-resolution image is obtained.

The invention discloses a reamer-pillar residual mining area upstream mining feasibility determination method suitable for dynamic disturbance loading and belongs to the technical field of coal mining. Firstly, the distribution positions of a reamer-pillar residual mining area and a remaining coal seam are ascertained, the rock formation composition, structure and physical and mechanical parameters of interlayer rock formations are obtained, and the interlayer rock formations are uniformly divided and numbered from bottom to top; then the position of a control rock formation is determined, themagnitudes of the disturbance loads of bearing pressure acting on a reamer-pillar residual mining area remaining coal pillar and the control rock formation after propagation attenuation are calculated, and finally, the stability of the reamer-pillar residual mining area remaining coal pillar and the control rock formation is analyzed by considering the effect of dynamic disturbance loading, to obtain a judgment result of the reamer-pillar residual mining area upstream mining feasibility. The method avoids the situation that the empirical method has large errors, and provides a theoretical basis for the safe mining of the upstream residual coal of the reamer-pillar residual mining area, improves the recovery rate of the coal resources in the upper part of the reamer-pillar residual miningarea, and effectively prolongs the service life of the mine.

The invention discloses a method for determining a safety distance between an overhead transmission line and a civilian unmanned aerial vehicle. The method comprises the following steps: A. determining an electrical insulation safety distance Di between the unmanned aerial vehicle and the transmission line based on a transmission line design specification; B, in consideration of the corona radio interference of the overhead transmission line, calculating a required protection distance Dp according to the characteristics of lateral propagation attenuation of interference; C. in consideration ofthe motion characteristics of the unmanned aerial vehicle, calculating a yaw distance caused by speed change of the unmanned aerial vehicle, a response delay buffer distance of the response delay anda hovering distance margin of the response delay, and adding the above distances to obtain the safety distance Dm between the unmanned aerial vehicle and the transmission line; and D. performing fusion calculation on the Di, Dp and Dm by using the Dimpster combination rule in the D-S evidence theory to finally obtain the safety distance DL between the overhead transmission line and the civilian unmanned aerial vehicle. By adopting the method, the leakage of the existing method for determining the safety distance between the civilian unmanned aerial vehicle and the overhead transmission line is compensated, and a basis is provided for obstacle avoidance early warning of the unmanned aerial vehicle.

The invention discloses a method for predicting electromagnetic environment distribution characteristics of a ship-borne radiation source in a formation, and the method comprises the following steps:calculating the near-region initial field distribution of a high-power radiation source according to the installation height position of the high-power radiation source in an offshore platform formation; establishing a forward propagation model in the high-power radiation source formation based on a two-dimensional scalar wave equation; establishing a near-sea-surface atmospheric refractive indexmodel based on near-sea-surface atmospheric characteristic analysis; calculating a propagation attenuation factor considering the influence of sea surface electromagnetic medium characteristics and near sea surface atmospheric refraction characteristics; and finally, solving the electromagnetic environment at the far field in the radiation source multi-platform formation by combining the directional diagram characteristics of the ship-borne high-power radiation source. According to the method, the electromagnetic environment parameters of the sensitive equipment in the water surface platform formation under the complex meteorological condition can be rapidly predicted, and electromagnetic environment input is provided for further carrying out accurate prediction and analysis on interference response of the sensitive equipment.

The invention relates to a method and a device for liquid level detection of a porcelain sleeve, a computer device, and a storage medium. The method comprises: sending an ultrasonic excitation signalto an ultrasonic probe, the ultrasonic excitation signal being used to control the ultrasonic probe to emit corresponding ultrasonic waves to a porcelain sleeve in a cable terminal; receiving reflected waves generated by propagation of the ultrasonic waves in the porcelain sleeve, and extracting to obtain reflected wave data according to the reflected waves; according to the reflected wave data, calculating propagation attenuation rate of the ultrasonic waves in the porcelain sleeve, according to the attenuation rate, compensating the reflected waves, extracting feature information of compensated reflected waves; according to the reflected wave feature information, determining a liquid level position in the porcelain sleeve, to obtain a determination result. Through calculating the attenuation rate of the ultrasonic waves in a transmission process, the reflected waves are compensated according to the attenuation rate. The liquid level position is determined by the compensated reflectedwave feature information, and a problem of reflected wave attenuation caused by uneven wall thickness of the porcelain sleeve is effectively prevented, and the liquid level position in the porcelainsleeve is accurately determined.

The invention discloses an integration method for predicating a ground wave propagation attenuation factor at high precision, comprising the following steps of: calculating an attenuation factor of a radio wave propagation path by using an integration equation method; selecting a number calculation area in terrain change violent and ground feature mutant local areas; selecting and using electric field distribution on the radio wave propagation incident surface of the area, which is calculated by using the integration method, as an exciting source; recalculating the propagation attenuation factor of the area by using an electromagnetic filed number calculating method; and replacing the attenuation factor calculated by number by the calculation result in the area through the integration method to obtain the attenuation factor of the whole propagation area. The invention can be used for reducing the error for predicating the terrain and ground feature mutant attenuation factor by using the integration equation method under the condition of adding the calculation resource at low amount.

The present invention discloses a feasibility determination method for upward mining of a pillar residual mining area in a static disturbance loading, and belongs to the technical field of coal mining. The feasibility determination method comprises the following steps of: firstly ascertaining the distribution locations of the pillar residual mining area and the residual coal seam, obtaining the composition, the structure, and physical and mechanical parameters of an interlayer rock stratum, and uniformly dividing and numbering the interlayer rock stratum from bottom to top; then determining the location of a control rock stratum, respectively calculating the magnitude of the disturbance load acting on the residual coal pillars and the control rock layer in the pillar residual mining area of a bearing pressure after propagation attenuation; and finally analyzing the stability of the residual coal pillars and the control rock layer in the pillar residual mining area in consideration of the effects of the static disturbance loading, figuring out the result of the feasibility determination for upward mining of pillar residual mining area. According to the feasibility determination method for upward mining of the pillar residual mining area in the static disturbance loading, the situation that errors of an empirical method are large is avoided, a theoretical basis for safety upwardmining of the residual coal in the pillar residual mining area is provided, the recovery rate of the upper coal resource in the pillar residual mining area is improved, and the service life of a mineis effectively increased.

The invention discloses an ultrasonic gas meter for civil use of an integrated transducer and a flow detecting method. The gas meter is composed of a data processing and control communication unit, atime measuring unit, an ultrasonic transmitting/receiving switching unit, an ultrasonic excitation unit, an ultrasonic receiving unit and a transducer integrated structure unit. An n-shaped measuringpipe integrates the transducer integrated structure to overcome the deficiencies that the ultrasonic propagation path is short, and the installment angle theta is not equal to 900; according to the actually-measured temperature, the ultrasonic propagation speed is corrected, the time receiving window is compressed, and the interference resistance capacity and accuracy of an ultrasonic flowmeter are improved; the acoustic impedance of an acoustic matching layer is between that of piezoelectric ceramics and that of a gas medium, the thickness of the matching layer is 1/4 of the wave length of the ultrasonic wave, the ultrasonic refraction propagation attenuation on different medium interfaces is reduced, and the accuracy of the ultrasonic flowmeter is improved. The time difference data utilizes a data cleaning technology to help to eliminate the influences of the complicated and changeable gas flow field on the accuracy.

The invention relates to a high-sensitivity and high-frequency broadband receiving cylindrical array implementation method. The method comprises the following steps of placing a plurality of ceramic particles in a column, arranging negative electrodes at the top, arranging positive electrodes at the bottom, spacing apart the negative electrodes from the positive electrodes through arranging a decoupling layer therebetween to enable the entire length to meet the requirement on the beam width, respectively connecting the negative electrodes and the positive electrodes of all ceramic particles in the parallel manner, leading out the negative electrodes and the positive electrodes of the ceramic particles through two wires, placing all parts in a positioning box to obtain a single receiving hydrophone, pouring the watertight polyurethane into the entire single receiving hydrophone to obtain a single receiving hydrophone module, and placing eight receiving hydrophone modules on an octagonal electronic cabin to finally obtain a receiving cylindrical array. According to the technical scheme of the invention, the front and back sides of ceramic particles are attached onto a copper backing and a matched layer, so that the operating frequency band of the hydrophone is effectively expanded. Therefore, the receiving sensitivity is improved. Moreover, the thickness of the matched layer and the thickness of the copper backing are reasonably selected, so that the receiving sensitivity of the hydrophone is increased along with the increasing of the frequency. As a result, the problem that the propagation attenuation difference between different frequency components of high frequency broadband signals is large can be solved.

The invention provides a reinforced concrete internal steel structure corrosion damage imaging device and a reinforced concrete internal steel structure corrosion damage imaging method. The device is simple in integral structural design and low in cost; by directly adoption of characteristics of high penetrability and propagation attenuation of the meter wave near field effect on dielectric materials, simplicity and directness in data processing and presenting, low complexity and easiness in implementation are realized; since near field waves can only propagate forward by an effective distance of a wavelength maximally, high locality and anti-jamming capability are realized, and imaging effects and processes are protected from influences of stray waves in general far field radar technology, and steel structure surface corrosion damage conditions can be accurately recovered and represented by reinforced concrete internal steel structure surface images obtained by imaging. In addition, owing to attenuation characteristics of near field waves, the imaging method is low in harms to testing personnel and can be widely applied to the technical field of reinforced concrete internal steel structure corrosion damage detection.

The invention relates to a method for testing accumulated damage effects of liquid nitrogen on fracture structures of water-containing coal samples. The method includes manufacturing coal samples; soaking the coal samples with different saturation degrees in the liquid nitrogen for single cycles and circularly soaking the coal samples in the liquid nitrogen for multiple cycles; weighing the saturated coal samples after each procedure to determine the increased weights of the coal samples and acquiring volume variation of fracture inside the coal samples by means of computing; observing fracture extension conditions of the surfaces of the coal samples before and after liquid nitrogen soaking tests for the coal samples by the aid of microscopes and measuring the increase quantities of the fracture; comparing propagation speeds of sound waves in the coal samples before and after the liquid nitrogen soaking tests and acquiring propagation attenuation speeds of the sound waves by means of computing so as to represent integral fracture conditions of the coal samples; measuring the uniaxial compressive strength of the coal samples, analyzing liquid nitrogen soaking effects of the coal samples with different percentages of saturated water contents and periodic circular liquid nitrogen soaking test results of the coal samples and drawing a conclusion. The method has the advantages that operation processes are simple, the method is high in applicability, fracture extension laws of liquid nitrogen soaking on the water-containing coal samples can be effectively reflected, and the method has an important reference significance on increasing permeability of coal beds, exploiting coal bed gas and increasing coal bed gas extraction rates.

The invention discloses a high-voltage cable insulating connector with a built-in VHF (very high frequency) partial discharge sensing device, and the insulator comprises the VHF partial discharge sensing device which can be respectively integrated with a first protective sleeve and a second protective sleeve in a matched and fastened manner, wherein the VHF partial discharge sensing device comprises an insulating ring; a VHF partial discharge sensor which is disposed in the insulating ring and is integrated with the insulating ring, wherein a binding post of the VHF partial discharge sensor isexposed outside the insulating ring; a clamping position capable of fastening the insulating ring together with the binding post at a mounting connection end; and an adapter assembly mounted on the second protective housing. The connector can solve the problem that the long-distance propagation attenuation of a VHF partial discharge signal is not detected, resulting in the inability to find the internal defects of the high-voltage cable insulating connector in time; the structural arrangement is more compact, which is convenient for maintenance, repair and cost control.

The invention discloses a fire monitoring network positioning method based on RSSI distance measurement. The method comprises the following steps: establishing a logarithmic distance path loss model; according to the position of a known reference node, periodically and dynamically measuring to obtain the received signal strength between the known reference node and a neighbor reference node, and obtaining a path loss index n value in a monitoring area at the current moment by using a logarithmic distance path loss model; calculating distances between a reference node and other reference nodes in the network by measuring a PR (d) value by using an RF signal propagation attenuation model, comparing the measured distance with an actual distance, and obtaining a measurement error of the PR (d) value at the reference node; and estimating the coordinates of the monitoring nodes by using a forgetting adjustment factor-based RLS positioning algorithm. According to the method, the influence of factors such as RSSI ranging errors and the number of reference nodes on the positioning precision can be fully considered, the positioning effect is ideal, and the positioning requirements of a fire environment monitoring system with a complex and severe network environment and limited positioning cost can be met.