83results about How to "Reasonable shape" patented technology

The invention discloses a three-dimensional human body model attitude and shape reconstruction method through a video sequence, and the method comprises the steps: 1), extracting two-dimensional jointpoints of a person in a video frame; 2), extracting facial feature points of the person in the video frame; 3), extracting a two-dimensional contour line of the person in the video frame; 4), estimating camera parameters, and generating a perspective matrix according to the camera parameters; 5), carrying out the optimization of the model posture and shape through an optimization method; 6), obtaining the edge points of the 3D human body model at the camera angle and the matching relationship between the edge point and the 2D contour line; 7), carrying out the re-optimization of the shape ofthe model through the optimization method so that the sum of the differences between the distances from the positions of the edge points of the three-dimensional model at the camera angle after projection to the positions of the two-dimensional contour points in the video frame is minimized. The method can avoid the posture turnover in the reconstruction process, and also can accurately reconstruct the posture of a head under the condition that the overall similarity of the model is guaranteed.

A tensioner for a traction drive includes a cylinder arranged in a housing at a distance to a housing wall to thereby define an interior space which contains hydraulic fluid. A piston is received in the cylinder for back-and-forth movement and bounds a pressure chamber containing hydraulic fluid. The piston has a cylinder-distal end which is operatively connected to a spring-biased tension roller supported on a traction member. Formed between the piston and the cylinder is a leakage gap, and a reservoir for hydraulic fluid is provided in an area of the leakage gap to prevent ingress of air into the pressure chamber, when the traction drive is at a rest.

The invention relates to a method for forging a workblank of a transmission disc of a locomotive. A selected raw material is cut into a blank according to weight; the blank is placed into a heating furnace to be heated to 1100 DEG C to 1180 DEG C; the heated blank is placed into a lower mold cavity of a pre-forging lower die to be positioned, the blank is forged to enable a material of the blank to flow in a pre-forging mold cavity of a pre-forging upper die and the pre-forging mold cavity of the pre-forging lower die in the free upsetting radial direction, and a molded pre-forging piece forms a corresponding thinning part at a protrusion bridge part and correspondingly forms a thickening part at the position of a cavity; the pre-forging piece is turned over to be placed into the mold cavity of the pre-forging lower die to be automatically positioned, the pre-forging piece is forged to enable the material of the pre-forging piece to flow in finish-forging mold cavities of a finish-forging upper die and a finish-forging lower die in the radial direction, and a molded finish-forging piece outwards extends along a disc body to form three uniformly-distributed lug parts and a shaft sleeve located at the middle portion of the disc body; and parting-line flashes of the finish-forging piece are cut off, connecting skin is punched away, and the workblank of the forging piece is prepared. By means of the method, the manufacturing cost is reduced, the production efficiency is improved, the complete streamline of a material of the transmission disc product of the locomotive can be kept, and the transmission disc of the locomotive has the excellent overall performance.

The invention discloses an aluminum profile frame structure of a cabinet used in electric power and electronic industries. The aluminum profile frame is composed of vertical, horizontal, and longitudinal profile beams and corner joints, and has a reliable and stable structure. The profile beam adopts the same cross-sectional size in three directions; the corner joints have guides, positioning structures and through holes for connection with the profile beam. The profile beams are easy to process, as long as the length of the profile beams is changed, cabinet frames of different sizes and specifications can be combined. The frame structure is suitable for standardized and batch production.

The invention discloses a friction-resistant aluminum alloy hub spinning process. Main procedures of the process comprise the steps of melting, casting pre-forming, homogenizing treatment, heating spinning, pre-heat treatment, shot blasting, spinning, heat treatment, shot blasting, machining and coating. Heat-spinning plastic deformation can make up superfine loosening defects, so that mechanical performance of a hub is improved; and the casting spinning new technology greatly improves the overall strength and corrosion resistance of a wheel, the machining allowance is greatly reduced, the service life of the wheel is significantly prolonged, safety of the wheel is significantly improved, vehicle weight reducing and oil saving are facilitated, and the wheel production cost is decreased.

The invention relates to a distracter applied to a renal transplantation operation. The distracter is provided with two handles, two distraction arms, two blocking pieces and a locking piece, wherein one end of each distraction arm is connected with the corresponding handle, and the other end of each distraction arm is connected with the corresponding blocking piece; the two distraction arms are hinged through a first hinging shaft; each blocking piece is provided with an upper blocking piece and a lower blocking piece; the upper blocking pieces are shaped into horizontal surfaces; the lower edges of the lower blocking pieces are overturned to the outer sides; sliding chutes are formed in the outer lateral surfaces of the lower blocking pieces, and first sliding teeth are arranged on the two sidewalls of the sliding chutes; the blocking pieces are regulated to be embedded into the sliding chutes through second sliding teeth on the two sides of the blocking pieces, and can move in the sliding chutes; the distraction arms are movably connected with the blocking pieces through second hinging shafts. The distracter is adjustable in distraction depth, and can be applied to fat and thin patients, and the operation field is fully exposed; the blocking pieces can rotate, so that the distracter is higher in flexibility; the locking piece is firmer; the whole distracter has the advantages of high practicability, simple structure and convenience in operate, and is suitable for clinical popularization and application.

Aluminum alloy wheel hot spinning process to improve the overall strength of the wheel. The main process of the process is melting-casting pre-forming-homogenization treatment-heating spinning-preheating treatment-shot peening-spinning-heat treatment-shot peening-machine Plus‑coating. The plastic deformation of hot spinning can bridge the fine loose defects, thereby improving the mechanical properties of the wheel hub. The new casting and spinning process greatly improves the overall strength and corrosion resistance of the wheel, while the machining allowance is greatly reduced, and the service life and safety of the wheel are improved. Significantly improved, which is conducive to vehicle weight reduction and fuel saving, and the production cost of wheels is reduced.

The invention belongs to the technical filed of explosive motors, and discloses an annular reciprocating type piston engine and an even permutation annular reciprocating type piston engine which are wildly suitable for different motive power machines such as motor vehicles, motor boats and small-size electric generators. The annular reciprocating type piston engine comprises an output main shaft, a transmission mechanism and an engine body. An air inlet valve, an air outlet valve, a piston assembly, an air cylinder assembly and a cam assembly are arranged on the engine body, wherein the engine body comprises a structural body, tow sides of the structural body are fan-shaped bodies, the air cylinder assembly is arranged on the structural body in an annular mode, the piston assembly is arranged inside the air cylinder assembly and reciprocates in an annular mode, and the central axis of the piston assembly and the central axis of the air cylinder assembly are coaxial with the axis of the output main shaft. The invention further discloses the even permutation annular reciprocating type piston engine. The annular reciprocating type piston engine and the even permutation annular reciprocating type piston engine are compact in structure and balanced in inertia force, improve mechanical efficiency of engines and prolong the service life of piston rings and the service life of air cylinders.

The invention relates to an asphalt concrete deceleration strip material as well as a preparation method and a construction technology thereof. The asphalt concrete deceleration strip material comprises the following components in percentage by weight: 2-4wt% of mixture of lignin fiber and polyester fiber, 85-90wt% of aggregate, 5-8wt% of mineral powder, 0.3-0.6wt% of an anti-rut agent and 2.7-6.5% of asphalt, wherein mass ratio of lignin fiber to polyester fiber is 1:(2-3), asphalt is one of SBS and SBR modified asphalt, and the mineral powder adopts limestone powder. The asphalt concrete deceleration strip material has the advantages that an asphalt deceleration strip made from the asphalt concrete deceleration strip material can realize forced deceleration and is reasonable in shape, no harm is done to a deceleration pavement and a vehicle, asphalt concrete material has good integrality with pavement, durable service is realized, a construction technology is simple, and cost is low; and the lignin fiber and the polyester fiber are doped into the deceleration strip material, so that stability and toughness of asphalt mixture are enhanced.

The invention discloses special zirconium-aluminium composite ground micro-powder for the optoelectronic industry and a production method for the same. The special zirconium-aluminium composite ground micro-powder for optoelectronic industry is produced from two main raw materials, namely, fused alumina and zirconium silicate, via ball-milling, water-washing, grading, compounding, surface coating, filtering, spray-drying and sieving, wherein the compounding ratios of the contents of the raw materials are as follows: the content of alumina particles is 30-50%, and the content of zirconium silicate particles is 70-50%. The product disclosed by the invention is reasonable in particle shape collocation, wide in particle size distribution, stable in median diameter, high in basic particle size ratio, without large particles and ultrafine particles, excellent in interparticle lubrication property, and especially suitable for grinding and polishing high-tech products in the optoelectronic industry.

The invention discloses a meridianal bias tire with low flatness ratio. The meridianal bias tire mainly comprises tread rubber, sidewall rubber, a tire bead, an air-tight layer, bead filler, tire body layers, a belt ply and a cap ply, wherein the laying direction of cord threads of the two tire body layers in a tread rubber area is along a meridian direction, and a tire body structure is a double-layer parallel stacked structure; compared with the bias tire, the high-speed performance of the tire is improved, the tire is easy to realize low flatness ratio, and the control stability of the tire is improved; the laying direction of the cord threads of the two tire body layers in a sidewall rubber area forms an included angle with the meridian direction, and the included angles of two tire body layers are equal in size and opposite in direction; the tire body structure is a reticular double-layer intersected stacked structure; as the tire body structure in the sidewall rubber area is a reticular intersected structure, the rigidity of the sidewall rubber is enhanced, the sidewall rubber is difficult to damage, the steering and braking performances and other performances of the meridianal bias tire are improved, the footprint area of the tire is reduced, the tire footprint shape is rationalized and the tire rolling resistance is reduced.

The invention relates to a processing method of a Pleioblastus amarus tea, and belongs to the technical field of Pleioblastus amarus processing. The processing method comprises the following steps: 1, carefully choosing a Pleioblastus amarus raw material; 2, cleaning and shelling; 3, scalding; 4, dicing; 5, lyophilizing; 6, roasting; 7, cooling; 8, sorting; and 9, packaging. The Pleioblastus amarus tea is suitable for most people, is convenient, and can be added with water to obtain a tea for drinking; and sugar or honey can be added to the Pleioblastus amarus tea when drunk, has no influences on the dissolve-out of substances, and has no influences on the health function characteristic of the Pleioblastus amarus tea. The Pleioblastus amarus tea has a slight bitter soup, a delicate fragrance and a tasty taste, has the medical efficacies of digestion promoting, heat clearing, vexation eliminating, fatigue eliminating, humidity eliminating, water retention alleviating, blood vessel protecting, ageing resisting, tumor resisting, lipid lowering, fat reducing and the like, and has the effects of bacteriostasis, anti-virus, anti-oxidation and radiation resistance.

The invention relates to a photocuring three-dimensional printer and a three-dimensional object molding method. The photocuring three-dimensional printer comprises a photosensitive resin groove; plane laser units are respectively arranged in at least two side surface directions of the photosensitive resin groove; the photosensitive resin groove has a transparent part; the plane laser units have lasers and focusing lenses; the lasers can generate plane laser beams; the focusing lenses are arranged on optical paths of the lasers; and focusing positions of the plane laser beams in the photosensitive resin groove are adjustable. The photocuring three-dimensional printer realizes the layer-by-layer curing of photosensitive resins, so that the molding efficiency is improved; and the control process of the plane laser beams is simpler and easy to operate.

The invention discloses a frameless wiper blade sheet steel forming and cutting-off all-in-one machine. The frameless wiper blade sheet steel forming and cutting-off all-in-one machine comprises a feeding mechanism, a machine frame, an electric control cabinet, a touch display screen, a strip material drawing mechanism , a sheet steel forming mechanism, a middle buckle notching mechanism and a two-end notching and cutting-off mechanism. The feeding mechanism is arranged on one side of the machine frame; the electric control cabinet is disposed at the bottom of the machine frame; the touch display screen is mounted on the machine frame; and the strip material drawing mechanism, the sheet steel forming mechanism, the middle buckle notching mechanism and the two-end notching and cutting-off mechanism are arranged in the machine frame in sequence from left to right and are arranged at certain intervals mutually. Multiple processes are integrated on the all-in-one machine, so that the production efficiency is greatly improved, the labor intensity of workers is relieved, the labor cost is reduced, the equipment cost is reduced, the equipment floor space is saved, product transferring is not needed, the yield is high, forming is more reasonable, and the product using effects are better.

The invention discloses a grid strain analysis method for thin plate forming and an application of the method, and relates to forming production techniques of metal materials such as automobiles and small metal components. The method comprises the following steps: firstly, directly drawing grid lines with the same length in a centralized limited strain area for forming metal plate workpieces and on the surface of metal plates, after stamping deforming, measuring direct deformation values of the grid lines with wrinkles or cracks in the centralized limited strain area, and respectively adjusting the process according to the calculated deformation situations. The method can be applied to stamping sites at any time, and is generally not limited by conditions. The method can be widely popularized and used in production lines, and is low in cost and easy to master.

The invention relates to an anterior cervical controllable advancement apparatus. The anterior cervical controllable advancement apparatus comprises a fixed arm, a movable arm, a gear rack, a grooved limiting rod and lifting rods, and further comprises a synchronous lifting component, wherein vertebral body screws are assembled at the lower ends of both the fixed arm and the movable arm; the gear rack and the grooved limiting rod are connected to the fixed arm and the movable arm and are capable of sliding relative to the movable arm; the lifting rods are inserted in a limiting groove of the grooved limiting rod; adjusting screw rods and adjusting nuts, which are sleeved, are arranged on the lifting rods; the adjusting nuts are embedded and retained on the upper side of the limiting groove; oblique through holes are formed in the lower ends of the lifting rods; and angle fixing nails are assembled in the oblique through holes. According to the anterior cervical controllable advancement apparatus provided by the invention, lateral approach of an anterior cervical body can be achieved, and advancement of vertebral bodies related to ossification of posterior longitudinal ligament can be conducted; the advancement apparatus is flexible to use, quantitative and controllable in operation and uniform in lifting; the advancement apparatus is good in operating effect and low in injury to patients; and the advancement apparatus has a broad clinical application prospect.

The invention provides a suspended ceiling and an installation method of thesuspended ceiling, and relates to the technical field of ornament. The suspended ceiling includes a support assembly, a bracket, connecting elements and two or moremetal wire mesh groups, the support assembly is used for supporting the bracket, each metal wire mesh group includes a plurality of ball-shaped metal wire meshes, each metal wire mesh is arranged on the bracket in a hanging mode by the connecting element, and two adjacent metal wire mesh groups are arranged in an overlapped mode and have different distances from the bracket. Two adjacent metal wire meshes of the suspended ceiling are arranged in the overlapped mode and have different distances from the bracket, the metal wire meshes arranged in the overlapped mode is simple in whole structure, reasonable in design, high in implementation and good in usage effect. The metal wire meshes are ball-shaped and reasonable in model, and after the overlapped arrangement, the metal wire meshes are good in tightness and overall usage effect. By using the suspended-ceiling installation method to install the suspended ceiling, the installation is simple in process, high in implementation and good in usage effect.

The invention relates to an asymmetric large-span spoke type cable-supported space structure. The cable-supported space structure comprises asymmetric spoke type radial arc-shaped upper chords, asymmetric spoke type lower chord radial cables, ring trusses and outer ring beams, wherein the ring trusses comprise ring truss lower chord ring cables, inner ring beams and ring truss vertical web members, the two ends of the ring truss vertical web members are hinged to the ring truss lower chord ring cables and the inner ring beams, diagonal web members are arranged between the adjacent ring truss vertical web members, the outer ring beams surround ring trusses, one ends of the asymmetric spoke type radial arc-shaped upper chord members are connected with the inner ring beams, the other ends of the asymmetric spoke type radial arc-shaped upper chord members are connected with the outer ring beams, the lowest points of the asymmetric spoke type lower chord radial cables are connected to the lower chord ring cables of the ring trusses, and the highest points are connected to the outer ring beams. According to the cable-supported space structure, upper chord bending members are changed into axial force members by utilizing the arc design of the upper chord arc-shaped rods, so that the complexity of an asymmetric structure is simplified, the stress is more reasonable, the steel consumption is obviously reduced, and the purposes of attractive building, simple structure, reasonable stress and material saving are achieved.

The invention relates to a construction method facilitating guarantee of hollow floor structural size. The construction method comprises the following steps that S1, a horizontal bottom formwork is laid; S2, a plurality of bottom layer steel bar cushion blocks are arranged on the bottom formwork, and a bottom steel bar layer is laid; S3, a plurality of second connecting pieces are used for connecting the bottom steel bar layer with the bottom formwork; S4, a plurality of placeholder box body cushion blocks are arranged on the bottom formwork, and a placeholder box body layer is laid; S5, an anti-floating steel bar layer is laid on the placeholder box body layer, and the anti-floating steel bar layer is supported by the placeholder box body layer; S6, a plurality of first connecting piecesare used for connecting anti-floating layer and the bottom formwork; S7, a plurality of top layer steel rib cushion blocks are arranged on the placeholder box body layer, and a top steel bar layer islaid; and S8, a plurality of third connecting pieces are used for connecting the top steel bar layer and the bottom steel bar layer. The anti-floating steel bar layer and the first connecting pieces are used for preventing placeholder box body tilting float after concrete slurry pouring, components in the floor are effectively fixed to guarantee the structure size of the floor to meet design sizerequirements and improve floor quality.

The invention discloses novel physiological-characteristic-based underwear for a man. The underwear comprises an underwear body, a first raised part for accommodating the penis and a second raised part for accommodating the testis, wherein the first and second raised parts are arranged on the underwear body. According to the novel physiological-characteristic-based underwear for the man, the penis is accommodated by the first raised part, and the testis is accommodated by the second raised part, so that the two most key physiological characteristics of the man are separately protected; and the underwear is rationally shaped and well adapted to the physiological characteristics of the man, the normal physiological development of teenagers is promoted, and a healthcare effect on the reproductive system of an adult is also achieved.

A device for dosing bulk material, in particular plastic granules, for machines that process plastic granules, in particular for injection moulding machines. The invention provides a bulk material feed (1), a material hopper (3) formed by multiple, preferably four, individually removable material hopper containers (2) and arranged under the bulk material feed (1) and ending in a dosing base device (4), and, optionally, a weighing container with a scale in the dosing base device (4). The individual material hopper containers (2) are arranged on a support spider (5) and the support spider (5) is formed by support spider plates (11) arranged vertically and perpendicular to one another. The support spider is mounted on the housing of the dosing base device (4). The support spider (5) has a height (h), which is at least the height (h1) of the material hopper container (2), which extends over the dosing base device (4), and corresponds to the immersion depth (h2) of the material hopper (3) into the dosing base device (4). A material hopper cover (6) is provided on the end of the support spider (5) facing away from the dosing base device (4).

The invention relates to a wool washing device which comprises a wool washing section and a drying section. The wool washing section comprises a first wool washing groove, a first padder, a second wool washing groove, a second padder, a third wool washing groove, a third padder, a fourth wool washing groove, a fourth padder, a fifth wool washing groove, a fifth padder, a sixth wool washing groove,a sixth padder, a seventh wool washing groove and a seventh padder; the first padder is connected with the second wool washing groove by a first flat curtain, the second padder is connected with thethird wool washing groove by a second flat curtain, the third padder is connected with the fourth wool washing groove by a third flat curtain, the fourth padder is connected with the fifth wool washing groove by a fourth flat curtain, the fifth padder is connected with the sixth wool washing groove by a fifth flat curtain, and the sixth padder is connected with the seventh wool washing groove by asixth flat curtain; a three-cylinder opening cleaner is arranged at a discharge end of the drying section. The wool washing device has the advantages that effects of washing out impurities in wool can be guaranteed, and the wool washing device is reliable in structure.

The invention discloses a pipe shaft door with protection function. The pipe shaft door with protection function comprises a door plate, a door frame and a switch; the door plate is jointed in the door frame, the switch is mounted at one side of the door plate. A wellhead protection plate is mounted at the outer side of the door frame, and an operation protection plate is mounted at the joint part between the door frame and the wellhead. The pipe shaft door with protection function overcomes the technical problem that the conventional pipe shaft door has no function of protecting the wellhead and the workers, the person can be effectively protected away from scratch by the walls while contacting the wellhead due to the wellhead protection plate mounted at the door frame and the operation protection plate mounted at the joint part between the door frame and the wellhead, and the person can be effectively protected by the operation protection plate away from scratch by the inner wall of the wellhead while the person enters into the wellhead for operating, the security is effectively guaranteed for the persons outside and inside the wellhead, and the pipe shaft door with protection function is attractive in appearance, reasonable in design and firm on structure.

The invention relates to a 30 degree parallel lens used for an ion implanter. The parallel lens comprises an upper magnetic pole and a lower magnetic pole whose structures and sizes are consistent and which are arranged in a longitudinally symmetrical state. An upper magnet yoke is arranged above the upper magnetic pole. A lower magnet yoke is arranged below the lower magnetic pole. A top surface of the upper magnetic pole is connected to a bottom surface of the upper magnet yoke. A bottom surface of the lower magnetic pole is connected to a top surface of the lower magnet yoke. The parallel lens is provided with two intermediate magnet yokes. Top ends of the two intermediate magnet yokes are connected to the bottom surface of the upper magnet yoke. Bottom ends of the two intermediate magnet yokes are connected to the top surface of the lower magnet yoke. The upper magnetic pole and the lower magnetic pole are arranged between the two intermediate magnet yokes. A lower magnetic pole surface of the upper magnetic pole and an upper magnetic pole surface edge of the lower magnetic pole are formed by a plurality of trajectories. In the invention, shapes of the magnetic pole surfaces are reasonable; an ion beam injection angle can keep the same, and uniformity and repeatability are guaranteed; incident ions are prevented from generating a channel effect on a lattice structure of a semiconductor chip; and uniform and needed channels can be generated.

The invention discloses a pair of separated half-open-crotch men's briefs. The pair of separated half-open-crotch men's briefs comprises a briefs body and a physiological containing portion, wherein the briefs body comprises a waistband, a front part, a rear part and a crotch, the physiological containing portion comprises a first containing layer, a second containing layer and a third containing layer, the first containing layer and the second containing layer are stacked from an inner layer to an outer layer and form a protruding cavity for containing the penis, the third containing layer forms a protruding cavity for containing the testicles, the left and right edges of the first containing layer and the left and right edges of the second containing layer are both in sewing connection with the front part, a first hole for the penis to stretch is formed at the position where the right edge of the first containing layer and the front part are sewed, and a second hole for the penis to stretch is formed at the position where the left edge of the second containing layer and the front part are sewed. The first hole and the second hole are formed in the first containing layer and the second containing layer in a staggered mode, so that the protruding cavity formed by the first containing layer and the second containing layer and used for containing the penis is adjustable in space size to adapt to different users.

The invention provides a head transmission mechanism of a computer-controlled flat-bed knitting machine, and belongs to the technical field of knitting machinery. The computer-controlled flat-bed knitting machine comprises a frame transversal beam. The head transmission mechanism comprises a motor, a left driving belt wheel seat, a right driving belt wheel seat, a left driving belt wheel, a right driving belt wheel, a traction driving belt wheel, a motor driving belt wheel, a traction driving belt and a main driving belt. The head transmission mechanism is characterized in that the left driving belt wheel seat is composed of a left driving belt wheel seat bottom board, a left driving belt wheel seat front side board and a left driving belt wheel seat rear side board; and the right driving belt wheel seat is composed of a right driving belt wheel seat bottom board, a right driving belt wheel seat front side board and a right driving belt wheel seat rear side board. The transmission efficiency is raised, the production efficiency is raised, the weight is reduced, material consumption is saved, and the left driving belt wheel, the right driving belt wheel and the traction driving belt wheel can be smoothly supported.

A technology for manufacturing the wheel rim as tyre holder of engineering machinery includes such steps as providing strip steel section, cutting short by required length, making bevel ends, forming a ring by die, heating for shaping, turning surface by 45 deg, and smoothing the connecting. Its strip steel section is also disclosed.

The invention discloses a manual and automatic integrated bolt opening mechanism which is mainly installed on a remote control weapon station. The manual and automatic integrated bolt opening mechanism is composed of components such as a machine base, a bolt opening motor, a bolt opening lever, a manual bolt opening assembly and a position sensor; and the manual bolt opening function and the electric control bolt opening function are achieved. The manual and automatic integrated bolt opening mechanism is arranged on the side face of a machine gun, local adjustment is carried out according to different matched gun types, and it is guaranteed that the machine gun can complete the bolt opening motion. During manual bolt opening, a bolt opening pull handle is held with one hand or both hands and is pulled in the gun tail direction until the bolt opening motion is completed, and the bolt opening pull handle is placed into a clamping groove; and during electric control bolt opening, a shooter operates a weapon control platform in a car to conduct electric control bolt opening operation, and finally bolt opening is completed. An original manual bolt opening mechanism can be replaced by the bolt opening mechanism, motion is reliable, the structure is compact, the weight is small, operation is easy and convenient, and maintenance is convenient.