43results about How to "Reduced range" patented technology

The invention discloses a stope bottom structure suitable for underground two-step mining and a production process thereof. An underground stope is divided into a room stope and a pillar stope. Bottom pillars are reserved according to the bottom structure forms. Along-vein travelling roadways (4) and across-vein ore-drawing roadways (6) are utilized to handle the ores. The blasting ores (11) in the stope are blasted and fall in trenches (12). A scraper pours the ores into an ore pass (5) via a common ore-drawing drift (9) and a room ore-drawing drift (10). After tailing-cemented filling of the room of the stope, new pillar undercutting roadways (8) are driven in the bottom pillars (3) during mining the pillar stope. The trenches (12) for room mining are formed through drilling and blasting and undercutting. The goafs formed after mining and ore-drawing of pillars (2) are filled. The stope bottom structure can serve two stopes, reduce the quantities and support quantity, reduce the mining and development ratio of mining, improve the stability and save the mining cost and preparation time of two-step mining.

The invention discloses a room-and-pillar major-diameter longhole inverted-step-like segmented lateral caving subsequent filling mining method for a steeply-inclined medium-thick orebody and gently-inclined and inclined extremely-thick orebodies with steady surrounding rocks at upper and lower panels. The method is characterized in that: an orebody is divided into panels, then the panels are divided into continuous single-stage stoping units, and mining is carried out by using a stoping sequence of stoping one unit every other unit, i.e., mining a room at first and a pillar next; when mining a room, a V-shaped trench bottom structure is employed, a longhole drilling chamber is arranged at the upper part of stope, bar-shaped pillars are left to support the top plate of the chamber, a down-the-hole drill is used for drilling rocks, an explosion mode of light section VCR method underholing inverted-step-like lateral caving with a common emulsion explosive is employed, access roads towards the room for ore removal are arranged in the pillars, and cemented roof-contact filling is employed; and during stoping of the pillars, access roads for ore removal are dug towards the pillars in cemented bodies in the room, a stoping manner for the pillars is identical to that for the room, and non-cemented filling with tailings and waste is employed. The method provided by the invention has the advantages of high security, a low production cutting ratio, great production capacity, low operation cost and small loss and dilution of resources.

The invention relates to a device and method used for offshore fertilization and pesticide application through an unmanned ship and a drone, and relates to the field of cultivation in water areas through assistance of an unmanned ship. The device consists of a cultivation carrier, an unmanned ship and a drone. A material filling device and a drone recycling device are arranged on an unmanned ship body. Through the cultivation carrier, materials are applied to a cultivation region, the drone detects condition information of the cultivation carrier and the unmanned ship helps the drone to supply materials for the cultivation carrier. Thus, improvement of efficiency for applying materials to the cultivation region is achieved; by applying the unmanned ship technology to the offshore cultivation industry, risks in offshore operation of fishermen are reduced; and efficiency of offshore operation is improved.

The invention discloses a mine down-hole double-stope bottom structure. Down-hole double stopes comprise a room stope and a jamb stope, vein-along transport tunnels (4) are arranged on two sides of the room stope and the jamb stope, and an ore winze (5) is vertically arranged outside the vein-along transport tunnels (4). A vein-passing ore removal tunnel (6) is arranged between the vein-along transport tunnels (4) along the stopes. A room bottom pulling tunnel (7) is arranged on the lower part of a room along the vein-passing direction, and a room ore removal access (10) and a shared ore removal access (9) are distributed between the room bottom pulling tunnel (7) and the vein-passing ore removal tunnel (6) in turn; and the shared ore removal access (9) is obliquely crossed with the vein-passing ore removal tunnel (6), and the angle is 45 to 55 degrees. The structure can serve two stopes, reduce the project quantity and the supporting quantity and reduce the mining-cutting ratio of mining; the stability of the bottom structure is improved; and the recovery cost and the preparation time of two-step recovery are saved.

The invention discloses a synthesized pipe rack with a frame composite structure. The synthesized pipe rack comprises unit plate pieces positioned on the upper and lower surfaces, and side unit plate pieces positioned on two side surfaces; the unit plate pieces and the side unit plate pieces are combined and spliced to form unit pipe sections; the unit pipe sections are axially spliced to form the synthesized pipe rack; the unit plate pieces consist of plates, hollow second pipes positioned at two ends, and hollow first pipes positioned at the other two ends; the side unit plate pieces consist of plates, and hollow second pipes positioned at two ends; the second pipes are axial splicing ends of the unit pipe sections; and in splicing of the synthesized pipe rack, the first pipes form longitudinal beams of the synthesized pipe rack, and the adjacent second pipes are connected with each other to form a skeleton structure of the synthesized pipe rack. The longitudinal beams and the skeleton structure of the pipe rack bear main loads; a bridge steel web structure is formed to enhance the shearing resistance of the pipe rack, and is skillfully used; based on dual enhanced structures, the bearing capacity is greatly improved; and under the same filling height, wall plates with the structures are thinner, and materials are saved.

The invention discloses a correction method for the deviation of a magnetic compass, belonging to the technical field of the deviation elimination method of a magnetic compass. The invention comprises the following steps: firstly, calculating accurate deviation coefficient of the magnetic compass, and secondly, eliminating four main deviation forces in a single magnetic heading direction. The invention has the advantages of little ground dependence, simple process, easy implementation, reduced range, fuel saving, software calculation and high automation degree.

The invention discloses a route planning safety assessment method for an unmanned aerial vehicle. The method comprises the following steps: (1) calculating the central point coordinates and principledirection semi-diameter of a bounding box according to an OBB bounding box construction algorithm; (2) calculating the covariance matrix eigenvalue and eigenvector of the OBB bounding box by using a Jacobi iterative algorithm; (3) constructing a no-fly zone and an unmanned aerial vehicle bounding box respectively, carrying out safety assessment on the route of the unmanned aerial vehicle by usinga collision detection algorithm of the bounding box, if the route of the unmanned aerial vehicle goes through the no-fly zone, the route does not meet the safety requirement. According to the method,by using the collision detection principle of the bounding box, whether the route of the unmanned aerial vehicle goes through the no-fly zone can be judged accurately, the method is safe and reliable,the resources are not wasted, and a solution is provided for the route planning safety analysis for the unmanned aerial vehicle.

The invention discloses a segmentation-based super-low altitude flight control method for a pilotless aircraft. The method comprises the steps of: judging the flight mode of the pilotless aircraft according to a preset flight mode judging condition of the pilotless aircraft, wherein the flight mode is divided into super-low altitude flight mode, super-low altitude level-off flight mode, and super-low altitude quitting flight mode; determining the longitudinal segmented flight control strategy of the pilotless aircraft in the super-low altitude flight mode according to the judgment result, anddesigning the longitudinal segmented control law of the pilotless aircraft; and refining specific control logic and control law parameters. According to the segmentation-based super-low altitude flight control method for the pilotless aircraft, the pilotless aircraft can enters super-low altitude flight mode in a relatively stable posture under a small disturbance environment; the flight range isshortened, and the oil consumption is reduced; and after the pilotless aircraft quits the super-low altitude flight, the pilotless aircraft can climb at the maximum dynamic pressure with an allowed overload, and then enters a second super-low altitude flight or returns.

The invention discloses a revegetation method for a biomass landfill. The revegetation method includes that planting soil mixed with organic fertilizer and turfy soil is added into a soil layer for planting pioneer plants to change secondary bare land with brushwood and bosk into forests; soil property of biomass-covered soil is improved by utilizing planting soil to guarantee planted plants not prone to death caused by the influence of gas, liquid and energy generated from biomass degradation; and meanwhile revegetation work amount and investment are reduced and soil utilization rate is increased, and harmful environmental effect from soil bareness is reduced.

The invention provides a memory programming method and device, an electronic device and a readable storage medium. The memory programming method comprises the following steps:1) programming a to-be-programmed memory cell in a memory by adopting an initial programming voltage; 2) verifying whether the memory cells finish programming or not, and classifying the memory cells which do not pass the verification according to the programming speed; and 3) respectively reprogramming the memory cells which do not pass the verification and have different programming speeds by adopting different programming voltages. Through introducing the novel memory programming method and device, the electronic device and the readable storage medium, the programming speeds of the memory units are classified in the verification process after programming, and different programming voltages are applied to the memory units with different programming speeds during reprogramming, so that the interval range of the threshold voltage is further reduced, and the reliability of the memory is ensured.

The invention is a small measuring range force transducer and a method thereof for indirectly measuring axle load. Two ends of a loaded axle are respectively provided with a small measuring range force transducer provided with a strain beam for sensing bent normal stress. The invention uses the principle that under the action of loading, the deflection of some point of the loaded axle is equal to that of the point of the small measuring range force transducer, adopts the small measuring range force transducer to sense the deflection generated by stress of the loaded axle, determines the measuring range of the transducer and parameters of a stress region by the design specification of the deflection and stress transducer, and manufactures the transducers suitable for the above indirect measurement. The invention completely avoids the traditional design thought directly measuring the axle load, changes the direct measurement of the axle load into indirect deflection measurement, reduces the measurement range and volume of the transducer greatly, and achieves the special skillfully deflected effect.

The invention discloses an unmanned aerial vehicle system for detecting natural gas leakage and a detection method. The unmanned aerial vehicle system comprises a flight control system, an information acquisition system and a ground control system. The flight control system controls the unmanned aerial vehicle to automatically take off and land according to the received instruction and to patrol and fly according to a route; the information acquisition system comprises a camera module and a sensor module, the camera module is used for acquiring image information in the inspection process, and the sensor module comprises various sensors for acquiring real-time flight state information of the unmanned aerial vehicle and a laser methane measuring instrument for detecting leakage; the ground control system comprises an instruction sending module, a communication module, an information processing module and a database, and the information processing module receives and processes the collected information through the communication module to generate a real-time electronic map of the methane concentration. The efficiency and quality of inspection work can be improved, and rapid information processing is realized.

The invention discloses a riverway flood discharge and treatment system, which comprises a plurality of flood discharge dams arranged in a riverway, a water outlet is formed in the bottom of one sideof the first flood discharge dam, a dosing area, a settling area and a water purification area are sequentially arranged on the downstream of the water outlet, a slow flow structure connected with thewater outlet of the flood discharge dam is arranged in the dosing area, and a mud scraper is arranged in the settling area. The mud scraper is connected with a driving system arranged on a river bank, and a water purification device is arranged in the water purification area. The system is simple in structure, low in cost, high in pertinence, high in efficiency and good in effect, segmentation and timely treatment of a river channel can be effectively achieved, and the river channel treatment work amount and treatment difficulty are greatly reduced; the multiple flood discharge dams are arranged and used for guaranteeing normal operation of the water treatment system, the flow speed and flow of the riverway can be guaranteed, safety around the riverway is guaranteed, and practicability ishigh.

The invention belongs to the technical field of arch bridge construction, and relates to a single-arch-rib framing swivel construction steel box arch bridge and a construction method thereof. The archbridge comprises a lower rotating disc located on a foundation, a horizontal rotating system fixedly installed on the lower rotating disc, an upper rotating disc installed on the horizontal rotatingsystem in a rotating mode, two sets of bridge deck longitudinal beams fixed to the upper rotating disc, and a vertical rotating hinge installed on the inner side of the upper rotating disc and used for fixing an arch rib to be constructed. The upper rotating disc, the lower rotating disc and arch ribs are arranged in a left-right framing manner, transverse supports and inter-rib cross beams are arranged between the left framing arch rib and the right framing arch rib, a suspender cross beam is fixedly mounted between the bridge deck longitudinal beams, suspenders are arranged at equal intervals along the longitudinal direction of each arch rib, the upper ends of the suspenders are anchored to the arch ribs, the lower ends of the suspenders are anchored to the suspender cross beams, a plurality of secondary cross beams are arranged between the suspender cross beams, and the suspenders, the suspender cross beams, the secondary cross beams and the bridge deck longitudinal beams are connected to form a lattice system in order to construct a bridge deck framework. The construction method guarantees the construction quality of the arch bridge, reduces safety risks and construction cost,and achieves convenient construction.

The invention discloses a mountain river pebble beach group linked renovation method based on a gradient principle. The mountain river pebble beach group linked renovation method is characterized by setting two control conditions needed in shoal channel flow renovation, namely the unit discharge control condition and the gradient control condition, and construction and management are conducted by obtaining submerged dike specification data through a water conservancy simulation test according to the control conditions. In the control conditions, the linkage condition and the gradient principle of riverbeds are sufficiently considered, the number of model test groups is greatly reduced, the shoal renovation success probability is improved; finally the channel size can be better improved, the flow state can be improved and the silt is prevented from accumulating in the channel after obtained submerged dike data are implemented. Meanwhile, the submerged dike has the advantages of being simple in structure, fast and convenient to implement, low in implementation cost, good in strength and impact resistance and long in service life, and is suitable to be used in mountain rivers.

The invention discloses an intelligent rain and sewage diversion device and belongs to the technical field of environmental protection. The intelligent rain and sewage diversion device comprises a diversion cabin, an information measuring unit, an intelligent control unit, a sundry crusher and a diversion device. The diversion cabin is used for caching a water body before diversion and is used asan equipment main body to be connected with other parts of integrated equipment and an external underground pipeline; the information measuring unit is used for measuring to obtain various hydrological and water quality data of the water body in the diversion cabin and used as a decision basis for diversion control; the intelligent control unit is used for calculating to obtain a current diversionscheme based on the hydrological and water quality data and an intelligent control algorithm and sending an intelligent control instruction to each component; the sundry crusher is used for crushingsundries in the water body of a water inlet pipeline; and the diversion device is used for controlling the flow of a drainage pipeline according to the intelligent control instruction. The diversion cabin is used as a center for integrating all components into an integrated fully-closed device, the integrated fully-closed device is directly connected with a mixed flow pipeline, a rainwater pipeline and a sewage pipeline of an underground pipe network, the diversion of the rain and the sewage is realized by adopting a multi-dimensional diversion standard and an intelligent control method, and the intelligent rain and sewage diversion device is suitable for application of large-range multi-node diversion of the rain and the sewage in cities.

The invention discloses a mountain river pebble beach group linked renovation method based on a gradient principle. The mountain river pebble beach group linked renovation method is characterized by setting two control conditions needed in shoal channel flow renovation, namely the unit discharge control condition and the gradient control condition, and construction and management are conducted by obtaining submerged dike specification data through a water conservancy simulation test according to the control conditions. In the control conditions, the linkage condition and the gradient principle of riverbeds are sufficiently considered, the number of model test groups is greatly reduced, the shoal renovation success probability is improved; finally the channel size can be better improved, the flow state can be improved and the silt is prevented from accumulating in the channel after obtained submerged dike data are implemented. Meanwhile, the submerged dike has the advantages of being simple in structure, fast and convenient to implement, low in implementation cost, good in strength and impact resistance and long in service life, and is suitable to be used in mountain rivers.

The invention discloses an underground box type pipe gallery of a steel-concrete mixed type structure. The underground box type pipe gallery comprises box type pipe sections, wherein each box type pipe section is formed by splicing a top plate, a bottom plate and two side plates. The box type pipe sections are spliced in the axial direction to form the box type pipe gallery. Concrete longitudinal columns are arranged at axial edges of the box type pipe sections. Concrete transverse columns are arranged at the two ends of the top plates or the bottom plates. Concrete stand columns are arranged at the two ends of the side plates. The concrete transverse columns and the concrete stand columns are in end-to-end connection to form a frame type framework. In the underground box type pipe gallery of the steel-concrete mixed type structure, the longitudinal columns and the frame type framework bear the main loading, and the bearing capacity of the pipe gallery is increased; by means of a bridge steel web plate structure, shearing resistance of the pipe gallery is enhanced; the side plates or sheets in the pipe gallery serve as wall boards of the pipe gallery, also serve as web plates of the anti-shearing bridge steel web plate structure of the pipe gallery and are utilized ingeniously; on the basis of a double reinforcing structure, the bearing capacity of the pipe gallery is greatly increased; and under the circumstance that the filling height remains the same, the structural wallboards are thinner, and materials are saved.

The invention relates to an excavation method of a large-diameter cylindrical tailrace surge chamber and belongs to the technical field of water conservancy and hydropower underground engineering construction. The excavation method adopts the technical scheme that firstly, middle drift penetrating and reserved protection layer stage excavation are performed, partitioning penetrating is conducted from inside to outside, and thin-layer excavation and layer-by-layer supporting are adopted; stage adjustment and releasing of surrounding rock stress are achieved, and stress drastic adjustment aftersurrounding rock excavation decompression caused by deep-hole-bench large-charge blasting is avoided; fork segment tailwater pipes adopt pre-stressed anchor cable reinforced supporting and first-stageside wall and vault concrete pouring which are are combined, and the two adjacent tailwater pipes adopt the comprehensive excavation construction scheme of drift vertical excavation and layer-by-layer supporting, and the carrying capacity of a bottom fork reserved rock partition wall is remarkably improved. Since the two adjacent tailwater pipes adopt the comprehensive excavation construction scheme of drift vertical excavation and layer-by-layer supporting, the problems that the surrounding rock stress state after practical engineering construction excavation is implemented is complex, driftintersection positions have stress concentration and large plastic zones, and the construction technical difficulty is high are solved.

The invention provides a reinforcing method for additionally arranging a new arch ring under the main arch ring of an old stone arch bridge. The arch ring is newly arranged under the bridge, the bearing capacity of the bridge is improved, and the use safety of the structure is ensured. The construction process is simple, construction is convenient, and the reinforcing effect is good. The influenceon clearance under the bridge is reduced; a riverway under the bridge is trimmed; the riverbed is paved, the arch ring is newly arranged below the old stone arch bridge; compared with demolition andreconstruction, the reinforcing method has the advantages that the engineering scale is effectively reduced, the construction speed is high, the construction work amount and difficulty are reduced andthe cost is saved, constructors are reduced, the influence on the old structure is reduced, the special appearance of the stone arch bridge is retained; little impact is generated on the bridge traffic; trepanning device can meet trepanning work of old arch rings or foundation side walls with different heights and radians, the stability of the whole trepanning device during trepanning is improvedthrough cooperation and adsorption of negative pressure suction cups, trepanning work is completed twice at the same time, and meanwhile adjustment of the trepanning distance is facilitated.

The invention discloses structural steel for a polar-region icebreaking transport ship and a preparation method of the structural steel. The structural steel is characterized by comprising the following chemical ingredients by weight percent: 0.11-0.25% of carbon, 0.61-1.25% of silicon, 0.10-0.39% of manganese, less than or equal to 0.008% of phosphorus, less than or equal to 0.001% of sulfur, 0.35-0.89% of chromium, 0.11-0.20% of titanium, less than or equal to 0.003% of nitrogen, and the balance of iron and inevitable impurities. The yield strength of the structural steel is more than or equal to 500 MPa, the cold brittleness transition temperature is lower than or equal to minus 70 DEG C, the comprehensive performances of the constructed polar-region icebreaking transport ship are excellent, the voyage is shortened, the safety is high, the defects in the prior art that a low temperature ship cannot break ice and the icebreaking ship does not have the capability of transporting large cargos are overcome, and the structural steel is of great significance for the domestic ocean shipping in the north pole.

The invention relates to an unmanned automatic bait casting ship adopting variable-amplitude sectional operation, belongs to a bait casting device for special aquaculture and particularly relates to an unmanned automatic bait casting ship adopting variable-amplitude coverage, sectional operation and breakpoint cruising. The unmanned automatic bait casting ship adopting variable-amplitude sectionaloperation comprises an automatic bin and an unmanned automatic bait casting ship body, wherein the unmanned automatic bait casting ship body plans channels in a variable-amplitude manner, plans routes in a sectional manner, realizes automatic charging and dynamic adjustment, controls the operation state of a propeller and a bait casting machine according to target needs and the real-time state and completes all bait casting operation in the sectional manner. The unmanned automatic bait casting ship adopting variable-amplitude sectional operation is lightweight, can meet requirements of different culture scales and different culture stages and is single in specification, small in ship size, lower in cost, high in control accuracy and high in adaptability.

The invention discloses a high-maneuverability turning energy control method for a high-speed plane symmetric aircraft, a medium and equipment, and belongs to the technical field of aircraft guidancecontrol. The invention aims to solve the problem that a high-speed plane symmetric aircraft needs to consume energy and adjust the course through long-time large rolling maneuver in a test area, guarantees that the aircraft enters a landing area at the end point of the energy management section, provides an online energy management method without a large number of iterative computations, and solves the problems that when the aircraft is separated from boosting, energy dispersion is large, and missile-borne aircraft computing resources are limited. In the energy management section, the aircraftmakes large maneuvering turns in opposite directions twice to bend the trajectory, energy is consumed in the maneuvering process, the course is adjusted, and finally the aircraft enters a landing area.

The invention relates to an asphalt road based on thermal power plant existing road and a construction method thereof. The asphalt road based on the existing road of the thermal power plant comprises a road body and a road surface layer which are sequentially arranged from bottom to top, wherein the road body is a roadbed body of the existing road of the thermal power plant, and the road surface layer comprises a bonding layer and an asphalt layer which are sequentially arranged on the road body from bottom to top; the thickness of the asphalt layer ranges from 0.8 cm to 2.5 cm. The construction method comprises the following steps of S1, an existing road surface layer being cleaned, and a roadbed body of an existing road being obtained; S2, performing crack treatment on the roadbed body of the existing road to obtain a repaired road body; S3, spraying a bonding layer on the road body; S4, asphalt with the thickness of 0.8-2.5 cm being laid on the bonding layer, and an asphalt layer being formed; and S5, forming a new surface layer through rolling forming, and arranging the new surface layer on the road body. Compared with the prior art, the method has advantages of cost reduction, construction period reduction and the like.

The invention discloses an fabricated revetment. The fabricated revetment is formed by splicing a plurality of L-shaped prefabricated revetment sections, concave parts at the ends of every two adjacent L-shaped prefabricated revetment sections are spliced to form a groove after the two adjacent L-shaped prefabricated revetment sections are spliced, water stop materials are arranged in the grooves,the two ends of the water stop materials are fixed to reserved bolt holes in the ends of every two adjacent prefabricated revetment sections through bolts, expansion mortar is poured into the groovesand an assembling gap between every two adjacent L-shaped prefabricated revetment sections, and the surface of each assembling gap is provided with single-component polyurethane sealant. According tothe fabricated revetment, the problems of long cast-in-place revetment construction period, low speed and difficulty in guaranteeing the construction quality in the previous project implementation process are solved; the prefabricated revetment construction has little influence on the riverway and the surrounding environment, rapid construction and green construction of the riverway revetment canbe achieved, and the expected construction quality of the revetment is easy to guarantee; and The prefabricated revetment can be repeatedly used in long-term planning, the waste work amount is reduced, and high efficiency and environmental protection are achieved.

The invention discloses an underground box type pipe gallery of a steel-concrete mixed type structure. The underground box type pipe gallery comprises box type pipe sections, wherein each box type pipe section is formed by splicing a top plate, a bottom plate and two side plates. The box type pipe sections are spliced in the axial direction to form the box type pipe gallery. Concrete longitudinal columns are arranged at axial edges of the box type pipe sections. Concrete transverse columns are arranged at the two ends of the top plates or the bottom plates. Concrete stand columns are arranged at the two ends of the side plates. The concrete transverse columns and the concrete stand columns are in end-to-end connection to form a frame type framework. In the underground box type pipe gallery of the steel-concrete mixed type structure, the longitudinal columns and the frame type framework bear the main loading, and the bearing capacity of the pipe gallery is increased; by means of a bridge steel web plate structure, shearing resistance of the pipe gallery is enhanced; the side plates or sheets in the pipe gallery serve as wall boards of the pipe gallery, also serve as web plates of the anti-shearing bridge steel web plate structure of the pipe gallery and are utilized ingeniously; on the basis of a double reinforcing structure, the bearing capacity of the pipe gallery is greatly increased; and under the circumstance that the filling height remains the same, the structural wallboards are thinner, and materials are saved.

The invention discloses a reinforcement method for adding a new arch ring under the main arch ring of an old stone arch bridge. The invention improves the bearing capacity of the bridge by installing the new arch ring under the bridge, improves the bearing capacity of the bridge, and ensures the safety of the structure. The construction process is simple, the construction is convenient, and the reinforcement effect is good. In order to reduce the impact on the clear space under the bridge, the river channel under the bridge was repaired, the river bed was paved, and the arch ring was newly built under the old stone arch bridge. Compared with the demolition and reconstruction, the project scale was effectively reduced, and the construction speed was fast, reducing The amount and difficulty of construction, cost saving, shortening the construction work, reducing the impact on the old structure, retaining the unique style of the stone arch bridge, has little impact on the traffic on the bridge deck, and the opening equipment can meet the old arch rings or arches of different heights and radians. The opening of the foundation side wall is carried out, and at the same time, the negative pressure suction cup is used to cooperate with the adsorption to improve the stability of the entire opening equipment when opening the hole. At the same time, two openings are completed at the same time, and the spacing of the openings is convenient to adjust.