75results about How to "Parameters are easy to adjust" patented technology

The invention relates to a high-property optothermal transformation multiple-element alloy nitride film and a preparation method thereof. The preparation method comprises the following steps of successfully preparing a multiple-element alloy sputtering target material by adopting a powder metallurgic method and a vacuum arc melting method; preparing multiple-element alloy nitride films with different thicknesses by adopting a vacuum magnetron sputtering film coating process and changing sputtering time and working air pressure so as to provide a new material for a solar spectrum selective-absorption coating, wherein the typical structure of the solar spectrum selective-absorption coating is of a sandwich structure which includes an infrared reflecting layer, a dual-absorption layer and an anti-reflection layer, and the solar spectrum selective-absorption coating has higher absorption rate and heat stability. According to the preparation method, a single-layer multiple-element alloy nitride film is sputtered on a polished stainless steel substrate, the single-layer multiple-element alloy nitride film is detected to have higher absorption rate of 79.82% compared with other single-layer optothermal transformation films within a solar spectrum range, and the obtained multiple-element alloy nitride film is uniform in thickness and has good combining capacity and high-temperature resistant property with the substrate. The high-property optothermal transformation multiple-element alloy nitride film disclosed by the invention is suitable for a high-temperature vacuum heat-collecting pipe and has wide application prospect in the field of solar optothermal.

The invention relates to a track dip angle inversion controlling method of an aircraft based on a control force limitation situation. The track dip angle inversion controlling method comprises the following four steps of: step 1, constructing a longitudinal model of an aircraft and converting a state of the aircraft; step 2, carrying out an inversion control design based on saturated control input; step 3, verifying tracking performance and regulating parameters; and step 4, finishing the design. The invention aims at a longitudinal plane dynamic model of the aircraft, utilizes an input saturation error dynamic amplification method by defining an auxiliary analysis system to realize an inversion control method based on the saturated control input, and is applied to the control of a track dip angle of the aircraft. The invention has better practical value and a wide application prospect in an aerospace automatic control technical field.

The invention relates to a preparation method of a perovskite solar cell light absorption layer material methylamine lead dibromide. The preparation method comprises the following steps: mixing solid methyl ammonium bromide and solid lead dibromide, adding the mixture into a N,N-dimethyl formamide solvent, stirring uniformly to obtain a reaction solution, pouring the reaction solution in a container, applying a pulse electromagnetic field to treat the reaction solution, dropwise adding the treated reaction solution on a clean conducting glass substrate, performing low-speed spin coating and high-speed spin coating respectively to form a perovskite film with the thickness of 500-800 nm, then putting the perovskite film in a vacuum drying oven, and performing annealing treatment to obtain a methylamine lead dibromide film. The preparation method has the advantages that the preparation technology is simple, the preparation cost is low, the degree of crystallinity of the product can be improved by adopting the treatment of the pulse electromagnetic field, and the heat preservation time of annealing treatment is greatly shortened and is only 1 / 6 of that when the treatment of the pulse electromagnetic field is unadopted, so that the production cycle of the product is shortened, the energy resources are saved, and the preparation method is beneficial for industrial production.

The invention discloses a saw blade grinding machine which comprises a base, a saw blade positioning device, a grinding wheel feeding device, a grinding wheel device, a saw blade feeding device, a saw blade shifter and a power device, wherein the base is vertical, a plurality of through holes is arranged on the periphery of the bottom of the base, and the base can be fixed on the ground through a fixing device; the saw blade positioning device is fixed on a vertical wall plate of the base, and can be used for positioning a saw blade and regulating the center of a circle of the saw blade; the grinding wheel feeding device is arranged on a chassis at the top end of the base; the grinding wheel device is controlled by the grinding wheel feeding device to move up and down in a reciprocating manner so as to utilize a grinding wheel to grind saw teeth of the saw blade; the saw blade feeding device is arranged on the chassis at the top end of the base; the saw blade shifter is controlled by the saw blade feeding device to act on the saw teeth of the saw blade, so that the saw blade rotates and the saw teeth are fed to a grinding position one by one for being conductive to grinding; and the power device drives the grinding wheel feeding device and the saw blade feeding device.

The invention discloses a trajectory tracking control method and system based on longitudinal and transverse coordination. The trajectory tracking control method comprises the steps of information perception, trajectory planning, control layer modeling and driving execution. According to information perception, traffic environment information and vehicle state information of the intelligent vehicle are collected in real time; according to path planning, an expected path is planned according to information perception data; according to control layer modeling, a longitudinal and transverse coordination strategy is established according to a preview principle, an expected longitudinal and transverse control instruction is processed and the expected longitudinal and transverse control instruction is converted into an executable control instruction physical value; and according to driving execution, an execution mechanism of the vehicle is executed according to the physical value of the control instruction to realize the overall control of the vehicle. According to the method, a simple two-wheel dynamic model and kinematics are adopted for modeling the unmanned vehicle, feedback and feedforward steering control is designed through a backstepping method principle according to road information and vehicle motion characteristics, and compared with traditional PID control and nonlinearmodel prediction control, the accuracy and the real-time performance are improved.

The invention discloses a fixed-wing unmanned aerial vehicle cluster affine formation control method based on a pilot following mode, and the method comprises the steps: S1, determining a pilot and a follower in a fixed-wing unmanned aerial vehicle formation based on a pilot follower mode, determining the configuration of a nominal formation and a communication topological structure of a cluster, and calculating a stress matrix of the nominal formation; S2, acquiring flight states of pilots in the fixed-wing unmanned aerial vehicle formation in real time, controlling the pilots to move along an expected flight track, and controlling the pilots to cooperate with each other to generate an expected formation; and S3, using a formation tracking control law based on a stress matrix to control followers in the fixed-wing unmanned aerial vehicle formation to track the motion trail of the navigator, and meanwhile, controlling the followers to adjust the relative position relationship between the respective unmanned aerial vehicles under the action of cooperative control to realize generation and affine transformation of a target formation. The method has the advantages of high flexibility, high environmental adaptability, high control performance and the like.

The invention discloses a reservation control method for a direct expansion solar energy heat pump water heater and a direct expansion solar energy heat pump water heater. The method includes the following steps : the preset temperature Ts is set by users, the time required for hot water is set as the preset time t1, and the current temperature of a water tank is Tr; the amount of heating Q required for increasing the water temperature to the preset temperature is calculated; the heat pump heating power P is calculated; the heating time is delta t; t1-t2 and delta t is compared; if t1-t2 <= delta t, the heat pump is started at the current time t2, and if t1-t2 > delta t, the heat pump is started at t3. Based on the difference of the climate in various regions, the solar energy irradiationstrength and the environmental temperature, and the water temperature and time set by users, the starting time of the direct expansion solar energy heat pump water heater can be automatically determined and the water heating can be completed in advance; the illumination strength is introduced by the water heater through a photosensitive sensor, so that the solar energy radiation heat quantity canbe utilized better, and the parameters of the direct expansion solar energy heat pump water heater can be adjusted.

The invention discloses a method for controlling atmospheric plasma spraying of an easily-oxidized coating under the atmosphere open environment. According to the method, in the plasma spraying process, powder can be effectively prevented from being oxidized, the purity and the property of the coating are ensured, the oxidation-resisting property and the ablation-resisting property of the coating are improved, and the service life of the coating is prolonged. The method specifically comprises the points that before plasma spraying is carried out, an air flow channel is arranged outside a plasma spraying gun muzzle; the air flow channel is connected with a protection air bottle, and therefore the aim that the protection atmosphere environment is formed between the spraying gun opening and a base material can be achieved. Before the coating is sprayed, the protection air bottle is opened in advance, the protection atmosphere environment is formed, and then plasma spraying equipment is controlled to carry out spraying of the easily-oxidized coating. According to the method, manufacturing of a silicide coating under the atmospheric pressure open environment can be achieved, the process is easy to operate, parameters are easy to regulate and control, and the method is a high-efficiency low-cost coating manufacturing process.

The invention provides a Buck converter control method achieving second-order sliding mode control by adopting a DSP. The main circuit module comprises a Buck converter. The input end of the Buck converter is connected with a direct current source while the output end can be connected with a load for direct power supplying. The output voltage of the Buck converter is acquired by an ADC module of a DSP chip. An output voltage acquiring module comprises two high-precision resistors. A control module comprises a DSP control chip. The drive circuit module comprises an electric power field effect transistor drive circuit unit. A second-order sliding mode control algorithm is realized by DSP digital control. The second-order sliding mode control algorithm has the advantages of having strong conventional sliding mode disturbance rejection capabilities and lowering the switch loss of the Buck converter by making a control quantity switching frequency not excessively high by means of additional hysteresis control. The method is suitably used for the Buck converter having high output voltage disturbance rejection requirements and low circuit energy consumption. The method further has the advantages of parameter adjusting convenience, flexible algorithm modification, etc.

The invention provides a multi-complementary microgrid varied-time scheduling method and a multi-complementary microgrid varied-time scheduling device based on dynamic matrix control. The method comprises the steps of S1, predicting an overload requirement of a multi-complementary microgrid and overall output power of an uncontrollable microsource, and working out the overall output power of a controllable microsource according to historical data and weather information; S2, separately solving an optimal power flow via an economic optimal objective function by using the overall output power ofthe controllable microsource as a constraint condition, to acquire a desired value of the output power of each kind of controllable microsource; S3, using the desired value of the output power as aninput parameter, and separately solving a predicted value of the output power of each kind of controllable microsource according to a prediction model controlled by a dynamic matrix; and S4, correcting the predicted value of the output power and the actual measured value of the output power, and determining a scheduling scheme according to the corrected output power. The method and the device provided by the invention have the characteristics that the PID structure is simple, the parameter is convenient to adjust, and the DMC rolling optimization robustness is strong, the feedback correction link is introduced, and the affect of the random factor on the scheduling result is corrected.

The invention relates to a knowledge point learning duration prediction method suitable for adaptive learning and application thereof. The knowledge point learning duration prediction method comprisesthe following steps: collecting user learning data, wherein the user learning data comprises a pre-test capability value of a user knowledge point, an average use time of other learned knowledge points of a user, a user check analysis rate, a knowledge point mastery rate, an average use time of the knowledge points learned by other students, and a learning mode of the user; performing data preprocessing on the obtained data; constructing a prediction regression model, and obtaining parameters in the prediction regression model by adopting a linear regression method based on the preprocessed data; performing model diagnosis; and obtaining the user knowledge point prediction learning duration based on the prediction regression model using the obtained parameters. Compared with the prior art, the method has the advantages of more individualized learning process, high prediction accuracy, high scientific rationality and the like.

The invention provides a neural network compiling method and system, a computer storage medium and compiling equipment. The neural network compiling method comprises the following steps: translating anetwork file into an intermediate expression file; optimizing the intermediate expression file from the perspective of performance analysis and single-node and multi-node cooperation; generating a network template file based on a hardware interface from the optimized intermediate expression file; and compiling the network template file into an executable reasoning application. The invention aimsto design and achieve a compiling tool chain framework capable of automatically adjusting parameters and generating codes according to software and hardware information, intermediate representation and a corresponding optimization algorithm, so that when the compiling tool chain framework is used for calculating on a target chip and a network output result is not changed, a higher calculation rateand a smaller calculation time delay can be obtained in a shorter optimization time. A user can conveniently debug and adjust parameters by himself / herself.

The invention is an ultra-long stroke oil pumping machine, comprising supporting seat, balance weight dragging piece, flexible oil pumping rod dragging piece, reducing power-driven roller, shaft coupler, electric motor, intelligent control cabinet, base, foundation, braking system, swelling wheel, swelling wheel stand, balance weight shaft, and balance weight, and characterized in that two ends of the power driven roller are supported by the supporting seat and connected with the electric motor on the base through the shaft coupler, one end of the flexible oil pumping rod dragging piece is fixedly wound in the middle of the power-driven roller body and the other end is connected with an oil pump through a continuous oil pumping rod in the oil pumping well, the balance weight dragging piece is composed of two steel wire ropes and nonmetallic rope, one end of each of them is fixedly wound at one end of the reducing power-driven roller body, and the other end is connected with the balance weight placed in an underground balance weight shaft, the swelling wheel is installed on the front-side base by the swelling wheel stand, it can make the flexible oil pumping rod aligned with the well mouth by adjusting the swelling wheel stand, the braking system and the intelligent control cabinet are installed on the base and the base is installed on the foundation.

The invention relates to a method for preparing cobalt oxalate by a pulse electromagnetic field, which solves the problems in the prior cobalt powder manufacture of complex process, high cost and large particle size and irregular shape of cobalt powder. The method comprises the following steps: acidulating (NH4)2C2O4 solution and controlling the pH value of the (NH4)2C2O4 solution at 4-6; dripping the acidulated (NH4)2C2O4 solution into CoCl2 solution, wherein the mol ration of (NH4)2C2O4 solution to CoCl2 solution is 1:1-2:1, and the dripping speed is controlled to be 100-200 ml / min; reacting in thermostatic water-circulator bath at 20-45 DEG C; mechanically stirring during reaction; processing the reaction system by a pulse electromagnetic field, wherein the pulse voltage is 1-1000V, and the pulse frequency is 1-100Hz; carrying out filtration, washing, vacuum drying at normal temperature after the reaction is completed to obtain a cobalt oxalate sample; and putting the cobalt oxalate sample into a tube-type resistance furnace to perform thermolysis reaction, cooling to room temperature in the furnace to obtain cobalt powder as a thermolysis product of cobalt oxalate. The invention has the advantages of simple process, low production cost, good quality, no pollution to treated objects or surrounding environment and wide application range, and can obtain products with different shapes and particle sizes.

The invention relates to welding equipment, in particular to efficient laser continuous handheld welding equipment. The equipment comprises a cabinet; a continuous optical fiber laser is mounted on the inner side of the cabinet; an operation panel is mounted on the inclined surface of the upper part of the cabinet; and multiple optical cable placing bases are mounted at the top of the cabinet. Theefficient laser continuous handheld welding equipment further comprises a handheld laser rod connected with the continuous optical fiber laser. The efficient laser continuous handheld welding equipment adopts the continuous optical fiber laser, has the characteristics of small size, high energy, easy parameter adjustment and the like, realizes basic laser parameter control, and is suitable for more laser machining places with higher laser heat requirements; and the handheld laser rod can resist high-power laser radiation, is more portable, is controlled without wasting power, and is easier tomaster the strength.

The invention discloses a system for controlling a floor mopping robot to walk along a line on the basis of a PID control algorithm and a method for controlling the floor mopping robot to walk along the line on the basis of the PID control algorithm. The system comprises a floor mopping robot body, a left rotating wheel, a right rotating wheel, a bottom layer driving module, a control module and apower supply module, wherein the bottom driving module comprises a floor mopping robot body attitude measuring unit and a driving unit. The system for controlling the floor mopping robot to walk along the line on the basis of the PID control algorithm and the method for controlling the floor mopping robot to walk along the line on the basis of the PID control algorithm provided by the invention have the advantages that the attitude angle, the speed and the position (namely the offset distance) of a floor mopping robot in the advancing process are subjected to closed-loop control, so that thefloor mopping robot keeps walking along a straight line in the advancing process; the system and the method are applicable to floor mopping robots of various models; parameters can be conveniently regulated; the control is stable; and the intelligent control of the floor mopping robot is completed at low cost.

The invention discloses a pulsed infrared dust concentration detection circuit, which is composed of an analog circuit and a digital circuit. The analog circuit comprises four stages of operational amplifiers connected in order. The non-inverting end and inverting end of a first stage operational amplifier are connected by a phototube. The infrared luminous tube of the phototube is connected between the collector electrode and digital ground of a triode, an infrared receiving tube is connected between the non-inverting end and inverting end of the first stage operational amplifier. A capacitor C1 is connected between a power supply and the digital ground, a resistor R1 is connected between the power supply and the emitting electrode of the triode, a capacitor C2 is connected between the emitting electrode of the triode and the digital ground, and a resistor R3 is connected between the PWM port of the digit circuit and the base electrode of the triode. A single chip microcomputer emits PWM pulse to drive the triode by the resistor R3. Step-by-step amplification is employed to conduct signal processing, precisely control the effective signal amplitude, and maximumly reduce noise interference. The circuit is internally added with a charge storage and driving part circuit, can realize autonomous driving, and has no need for an additional external power supply.

The invention provides an image processing method and device, a medium and electronic equipment. The method comprises the following steps: acquiring a grayscale image of a to-be-restored image, performing filtering processing on the grayscale image by using a filter to obtain a filtered image, detecting image stripes in the filtered image, generating an image mask according to the image stripes, and repairing the to-be-repaired image according to the image mask to obtain a repaired image. According to the invention, the image mask for repairing the to-be-repaired image is generated through thedetected image stripes in the filtered image corresponding to the grayscale image, so that the function of repairing the to-be-repaired image is realized. On one hand, the edge information in the specific direction is directly obtained through the filter, the limitation of edge detection is eliminated and the detection efficiency is improved, and on the other hand, in the process of generating the filtered image and the image stripes, parameter adjustment is convenient, the complexity of time and space is reduced, and the effectiveness of stripe detection is improved.

The invention discloses a laser visualization processing method and system. The processing method comprises the steps that a product coordinate system, an image coordinate system and a drawing file coordinate system are established correspondingly; a to-be-processed graph is drawn on a drawing software interface of an industrial personal computer; an image of a product under the product coordinatesystem is acquired through a camera; according to the mapping relation between the coordinate systems, the product coordinate system is converted to the drawing file coordinate system, and an image of the product under the drawing file coordinate system is obtained; the product is processed according to the to-be-processed graph on the drawing file coordinate system, meanwhile, a processing planeis photographed through the camera, an image of the product in the processing process is obtained in real time, and the image is updated to the drawing file coordinate system in real time; and the graph on the drawing file is adjusted in real time according to the position of the product until the laser processing procedure of the product is completed. According to the method, the problem that atechnician cannot directly observe a product from a drawing file and needs to frequently confirm between the industrial personal computer and a processing table top back and forth when designing a galvanometer processing graph is solved.

The invention relates to a UPFC (unified power flow controller) three-phase imbalance optimization method based on nonlinear control. The method comprises steps as follows: 1), a modularized multi-level UPFC is constructed; 2), an inner current loop in a parallel side current converter adopts a passive sliding mode variable structure control mode, reactive regulation is performed through q-axis component, and active regulation is performed through d-axis component; 3), an inner current loop in a series side current converter adopts the passive sliding mode variable structure control mode, voltage with controllable amplitude and phase angle is injected by a series side transformer, positive sequence component is used for realizing phase shift adjustment and series compensation of alternating voltage, negative sequence component is used for offsetting negative sequence voltage component of an imbalanced part of an electric transmission line, and three-phase imbalance optimization is realized. Compared with the prior art, the method has the advantages of being high in dynamic response speed, high in robustness, safe, economic and stable and inhibiting zero-sequence current, and parameters are easy to adjust.

The invention provides a gravity balance difference pumping unit which comprises a frame, an upper platform fixed to the top end of the frame, a first drive oil cylinder, a second drive oil cylinder, gravity combination rollers, a drive oil cylinder pull rope, a balance weight pull rope, a pumping rod, balance weight iron and a hydraulic pump station. The first drive oil cylinder and the second drive oil cylinder are mounted on the front side and the rear side of the frame respectively, a piston rod of the first drive oil cylinder and a piston rod of the second drive oil cylinder are connected with a first movable pulley and a second movable pulley respectively, and the first movable pulley and the second movable pulley can slide up and down on a movable pulley slideway of the frame. The upper platform is connected with a supporting wheel and a front bearing gravity wheel. The drive oil cylinder pull rope is wound around the movable pulleys, the supporting wheel and the front bearing gravity wheel and fixedly connected to the gravity combination drive rollers. One end of the balance weight pull rope is connected with the balance weight iron, and the other end of the balance weight pull rope is wound around the supporting wheel and fixedly connected to the gravity combination rollers and connected with the pumping rod; under the action of the gravity combination rollers, the balance weight iron slides up and down along the slideway of the frame through the rollers on the two sides. According to the gravity balance difference pumping unit, output power is larger, a long stroke is reached, and the technical problems that a conventional pumping unit is low in efficiency and high in energy consumption.

The invention discloses an operating system recognition method based on a CAVWNB _ KL algorithm, which comprises the following steps: analyzing an operating system recognition rule in nmap, extractingM thousand data from a large number of split data sets as training data, and extracting m thousand data again as simulation test data by the same method; carrying out box sealing operation on the obtained M thousand data; calculating the correlation degree between the attributes and the classes by using KL divergence to serve as the weight of each attribute; calculating a prior probability and aposterior probability of the preprocessed M thousand data, and storing the prior probability and the posterior probability as fingerprints; calculating a test precision measurement index by taking themten thousand data set; calculating the test precision of the real flow; and screening the collected real flow, performing incremental training in a Bayesian incremental learning mode, correcting anoriginal fingerprint model, and completing recognition. According to the method, a CAVWNB _ KL algorithm is adopted, so that independent conditions required by naive Bayesian attributes are greatly relieved, and the classification precision is improved.

The invention belongs to the technical field of floating type ocean structure vibration control research, and provides a swing device for restraining large-scale floating type ocean structure large-amplitude vibration. A flexible, light and high-strength cloth is laid and connected to a large-area frame composed of longitudinal and transverse ropes and steel pipe beams; and the single-layer or multi-layer frame is suspended at a plurality of specified positions below the ocean structure by utilizing a plurality of high-strength ropes with enough tensile rigidity. When the floating structure drives the device to vibrate in water, the gravity of the device and the water body generate huge additional inertia force and additional damping force to do negative work, the vibration energy of the structure is consumed, and therefore the large-amplitude vibration of the device is restrained. In addition, the device and the structure are flexibly connected, so that vibration in multiple directions can be inhibited, and particularly, the vertical effect is optimal. The dead weight of the swing device and rope length are convenient to adjust, and control of different amplitudes is facilitated. Moreover, the device is simple in structure, easy in parameter adjustment, capable of controlling various vibrations, wide in application, practical, economical and excellent in comprehensive performance.

The invention discloses a remote sensing image target quick detection method based on rotating anchor point clustering. The method comprises the steps: firstly designing rotating anchor points based on a k-means clustering algorithm, and obtaining a series of rotating anchor points; performing foreground and background dichotomy and coordinate coarse regression on the rotation anchor point, and combining rotation non-maximum suppression post-processing to obtain positive and negative sample information and a simplified high-quality proposal; and finally, performing multi-scale rotation RoI pooling processing on the proposal to obtain a fixed-length vector containing the region of interest RoIs, inputting the vector into a full connection layer (FC) for specific category classification and coordinate regression, and performing INMS post-processing to obtain a final detection result of the target. According to the method, the redundancy of anchor points can be effectively reduced, the detection speed and the detection precision of a remote sensing image target are improved, the algorithm is easy to implement, parameter adjustment is simple and convenient, and the method has the advantages of mathematical interpretability and the like, and has wide application prospects and good economic benefits.

The invention discloses an SVG controller parameter identification method based on RTDS test data, and relates to a parameter identification method. At present, the efficiency is low due to the limitation of partial field test conditions and methods. The method comprises the following steps: carrying out in-loop test on SVG output responses of multiple control modes under multiple working conditions to obtain response output data; establishing a simulation system which is the same as the RTDS test environment in BPA software, and performing transient simulation calculation on the SVG controller; based on the RTDS in-loop test data, identifying the control parameters of the SVG controller by applying an automatic parameter identification algorithm, comparing the BPA simulation result with the RTDS in-loop test result, and calculating a control error; if the control error does not meet the requirement, performing iterative parameter correction by adopting a nonlinear least square identification method until an error index is met; and completing parameter identification work to obtain an SVG controller model and parameters. According to the technical scheme, simulation results are repeatable, parameters are easy to adjust, working conditions are easy to simulate, and test efficiency is high.

The invention relates to non-contact electromagnetic ultrasonic auxiliary welding equipment. The non-contact electromagnetic ultrasonic auxiliary welding equipment comprises a heat preservation chamber and a console; the heat preservation chamber is arranged on the console; a permanent magnet connecting column is fixed to a cross beam of the console; the lower end of the permanent magnet connecting column extends into the heat preservation chamber to be connected with a permanent magnet clamp; a permanent magnet is clamped by the lower end of the permanent magnet clamp; a workbench and a resistance heating device are arranged under the permanent magnet; the upper end of a lifting knob penetrates through the bottom face of the heat preservation chamber to be supported below the resistance heating device; a multi-turn coil is arranged between the permanent magnet and the workbench; the permanent magnet, the multi-turn coil and the workbench are arranged at intervals; the permanent magnet and the multi-turn coil are used for interacting to generate electromagnetic ultrasonic waves; a thermocouple is arranged at the bottom of the heat preservation chamber; the multi-turn coil and the thermocouple are both connected with the console; the heat preservation chamber is provided with an observation window and a glove connector; and the glove connector corresponds to the workbench. Ultrasonic waves are generated in liquid brazing filler metal in situ, oxidation films on the surfaces of base metal and the liquid brazing filler metal are removed, and effective connection of welding joints is achieved.

The invention relates to a passive sliding mode variable structure control method of an MMC STATCOM, and the method is used for controlling an STATCOM device. The STATCOM device is a modular multilevel converter connected with an alternating current power grid, and the method comprises the following steps: adopting a voltage and current double-closed-loop decoupling control strategy based on a dqrotating coordinate system to carry out reactive power regulation through q-axis components to generate or absorb reactive power, so as to stabilize the AC bus voltage of the access point; carrying out active adjustment through a d-axis component, absorbing active power from a power grid AC bus to compensate active power loss of the converter, so the stability of the voltage of the direct-currentside of the converter is maintained. Compared with the prior art, the method has the advantages that the control system has high robustness and anti-interference capability on external disturbance andinternal parameter change, so that the control quality is improved. Compared with a traditional double-closed-loop PI, the method has the advantages that parameters are easy to adjust, the dynamic response speed is high, and robustness is high.

The invention discloses an alternative gap regular octagon-shaped dual-band electromagnetic metamaterial structure. The alternative gap regular octagon-shaped dual-band electromagnetic metamaterial structure includes a dielectric substrate; a surface of the dielectric substrate is etched with an internal regular octagon-shaped metal sheet and an external regular octagon-shaped metal sheet, the maximum radius of the internal regular octagon-shaped metal sheet is smaller than the minimum radius of the external regular octagon-shaped metal sheet, each interval side of the internal regular octagon-shaped metal sheet and the external regular octagon-shaped metal sheet is provided with a gap, and the gaps of the internal regular octagon-shaped metal sheet and the external regular octagon-shaped metal sheet are distributed in an alternative manner; and the other surface of the dielectric substrate is etched with a metal strip, and the length of the metal strip is equal to the length of the dielectric substrate. The alternative gap regular octagon-shaped dual-band electromagnetic metamaterial structure can meet applications requiring dual-band performance indexes.

The invention belongs to the technical field of coal-bed gas exploitation and particularly relates to a hydraulically driven coal-bed gas well discharge and mining tubing pump. The hydraulically driven coal-bed gas well discharge and mining tubing pump comprises an adapter flange joint part, a power cylinder part, a power cylinder plunger pump joint part and a plunger pump part. The power cylinder part comprises a rodless cavity power pipeline, a rod cavity power pipeline, a cylinder bottom, a power cylinder inner barrel, a piston, a piston rod, a guide sleeve and a power cylinder outer barrel, wherein the upper end and the lower end of the power cylinder outer barrel are connected with the adapter flange joint part and the power cylinder plunger pump joint part respectively, the upper end of the power cylinder inner barrel is connected with the cylinder bottom, the lower end of the power cylinder inner barrel is connected with the power cylinder plunger pump joint part through the guide sleeve, the piston rod is in sliding connection with the guide sleeve, the upper end and the lower end of the piston rod are connected with the piston and a plunger of the plunger pump part respectively, and the rodless cavity power pipeline and the rod cavity power pipeline communicate with a rodless cavity and a rod cavity of the power cylinder part. According to the hydraulically driven coal-bed gas well discharge and mining tubing pump, hydraulic rodless discharge and mining are adopted, and the rod and tube eccentric abrasion problem is solved.