83results about How to "Reduce stress shielding" patented technology

This invention discloses a beta-type Ti alloy with low elastic modulus for mrdical application. The Ti alloy comprises: Nb 30-37%, Zr 0-20%, and Ti. The cast structure of the Ti alloy is beta phase. The Ti alloy has moderate strength, and can satisfy the strength requirement for clinical bearing material. The elastic modulus of the Ti alloy is only 45-55% that of Ti-6Al-4V alloy. The alloy is a casting alloy, and has no noble metals added such as Ta, thus effectively lowering the cost. Besides, all the added elements have biocompatibility, and toxic elements are avoided. The Ti alloy has high biocompatibility and mechanical compatibility, and can be used to produce bone plates with reduced stress shielding effect.

The invention discloses a full coax femoral head prosthetic appliance and its making process, wherein the prosthetic appliance comprises an inner layer and an outer layer, the inner layer being an uninterrupted carbon fiber reinforced polyetheretherketone composite material layer, the outer layer being a short cut carbon fiber reinforced polyetheretherketone composite material layer, and a core rod die arrangement and a prosthesis die arrangement are utilized to realize thermal compression bonding of the two composite material layers. The invention also discloses the process for making the prosthetic appliance.

The invention relates to an artificial total knee replacing prosthesis which can reconstruct anterior cruciate ligament and comprises a tibia platform supporting part and a liner. The tibia platform supporting part consists of a horizontal platform and a rod part which are fixedly connected; the surface of the liner is provided with a pair of spherical concaves horizontally intervened so as to respectively receive a femur scleromere. The pad and the tibia platform supporting part are provided with a pore canal which respectively penetrates the pad and the horizontal platform of the tibia platform supporting part and are communicated with each other, so as to lead the anterior cruciate ligament to pass through the pore canals, the two ends of the ligament to be fixed on the tibias of a femur ectocondyle, and the horizontal platform of the tibia platform supporting part; thus realizing the reconstruction of the anterior cruciate ligament in a replacing surgery of the artificial total knee.

The invention relates to a fusion instrument under a mirror, in particular to a distractable fusion cage with the adjustable middle bone grafting height. The distractable fusion cage comprises a supporting platform, a support and an adjusting assembly, adopts an internal hollow and external hollow design, has a large bone grafting space and facilitates bone grafting, so that the stability of the lumbar vertebra can be better established and maintained after the fusion cage is implanted, the parallel distracting function of the fusion cage main body can be achieved, the lifting height is increased, the distractable fusion cage adapts to the heights of intervertebral spaces of different segments, the application range is wide, and the overall cost is low.

The invention relates to an artificial hip joint with surface nanometer and porous structure in the technical field of medical appliance and a preparation method thereof. In the artificial hip joint, the part of a femoral head handle or / and acetabulum combined with human organism has a scale of surface layer grains of between 1 and 500nm, and has an evenly distributed porous structure; and the artificial hip joint has a gradient nanometer structure from the surface inwards, the scale of the grains gradually increase along with increase of distance with the surface, until a scale of a conventional untreated state is achieved, and the thickness of the gradient nanometer layer is between 1 and 500 mu m. The preparation method comprises the following steps that: the artificial hip joint obtains the nanometer gradient structure layer by surface high-energy treatment technology; and then, the nanometer gradient structure layer is subjected to acid treatment so as to obtain a porous structure on the surface, thereby obtaining the artificial hip joint. The artificial hip joint and the method not only can effectively reduce stress shield effect of an implant body and a bone, but also can improve interface combination of the prosthesis and the bone, effectively improve the loosened implanted prosthesis, and have excellent application in the field of biomedicine.

The invention discloses a nanocomposite intervertebral fusion cage and a preparation method thereof. The nanocomposite intervertebral fusion cage is provided with a substrate structure, the substrate structure passes through central holes of upper and lower end faces of the fusion cage, and the upper and lower end faces of the substrate structure are two rough surfaces in a dentiform structure; the side face of the substrate structure is provided with side holes communicated with the central holes; and the front end part or rear end part of the substrate structure is provided with a clamp hole with a thread along the application direction of the substrate structure, and the two sides of an external aperture of the clamp hole are provided with a concave clamp structure, wherein the two sides in an opposite angle direction of the upper end face or the lower end face of the substrate structure are respectively provided with a coplanar metal positioning structure, and an end part at which a non-threaded hole on the other end face of the substrate structure is arranged is provided with an antarafacial metal positioning structure. The nanocomposite intervertebral fusion cage is prepared through the steps of injecting molten nano-hydroxyapatite / polyamide composite materials into a moulding mould at a temperature of 220 to 280 DEG C and under the pressure of 80 to 130MPa, then carrying out cooling and moulding on the obtained product so as to obtain the intervertebral fusion cage. The nanocomposite intervertebral fusion cage has the advantages of excellent bioactivity, excellent biocompatibility and mechanical property matched with the human body, and capability of facilitating to determining the position and height of the nanocomposite intervertebral fusion cage implanted in an X-ray sheet.

The invention relates to a novel cervical vertebra dynamic internal fixing device, which comprises an artificial cervical vertebra body and an artificial intervertebral disc. The artificial cervical vertebra body is inlaid on any vertebral body of the third section to the seventh section of partially cut human cervical vertebra. Two screw holes and two clamping grooves are symmetrically arranged on the artificial cervical vertebra body. A vertebral pedicle screw which is fixedly connected with the section of the human cervical vertebra body and a vertebral pedicle is arranged in each screw hole in a penetrating way. A vertebral pedicle screw lock pin cross bar is positioned and clamped between the two clamping grooves. The artificial intervertebral disc is arranged at the upper end and the lower end of the artificial cervical vertebra body, is arranged at a vertebral gap between an upper vertebral body and a lower vertebral body close to the position of the artificial cervical vertebra body, and comprises artificial nucleus pulposus and an artificial end plate. A screw hole is arranged on the artificial end plate. An artificial end plate fixing screw which is fixedly connected with the corresponding section of the artificial cervical vertebra body is arranged in the screw hole in a penetrating way. By adopting the internal fixing device, the invention has the advantages that the surgical invasion is small, the operation is easy and the dynamic fixation of the cervical vertebra after the subtotal excision of an anterior cervical single vertebral body can be realized.

The invention discloses a multihole titanium-magnesium alloy artificial bone capable of promoting bone growth and a preparation method thereof. The artificial bone is prepared from titanium-magnesiumalloy powder. The titanium-magnesium alloy powder is prepared from the following components (in percentage by weight): 0.3 to 9.5 percent of molybdenum, 1.5 to 6.5 percent of nickel, 2.5 to 14.5 percent of cobalt, 1.5 to 3.5 percent of yttrium, 1.5 to 5.5 percent of niobium, 2 to 3.0 percent of magnesium and the balance of titanium and unavoidable impurities, wherein the total percentage of all the components is 100 percent. Compared with the prior art, the multihole titanium-magnesium alloy artificial bone has the advantages that due to the addition of a molybdenum element, the intensity of the artificial bone is enhanced, and the low-temperature characteristic of the artificial bone is improved; meanwhile, according to an improved formula and an improved process, the density, the elasticity modulus, the compressive yield strength and the fracture toughness of the titanium-magnesium alloy artificial bone are closer to corresponding values of a human bone; furthermore, the artificial bone can achieve a mechanical property matched with a bone tissue by adjusting the porosity, so that a stress shielding phenomenon between the titanium-magnesium alloy artificial bone and the bone tissue is relieved.

The invention provides acrylic compound bone cement with a partial degradation function and a preparation method of the acrylic compound bone cement with the partial degradation function. The acrylic compound bone cement is composed of acrylic polymer powder, contrast medium doped solid powder, acrylic monomers and a pore-forming agent with a degradation function, and the pore-forming agent is made from degradable microspheres or particles 100-1500 micrometers in diameter. Compared with acrylic bone cement in the prior art, the acrylic compound bone cement has the advantages that partial degradation is realized, voids generated in degradation of the pore-forming agents enable growth of new bones, the new bones and the undegraded bone cement are engaged mutually to form a steady interfacial bonding function, and accordingly the risk of looseness of the bone cement can be remarkably reduced. In addition, the modulus of compression of the acrylic compound bone cement is low and closer to that of autogenous bone, and the risk of degeneration or fracture of adjacent segments can be effectively reduced.

The invention discloses an absorbable orthopedic internal fixation material based on silk fibroin and a preparation method thereof. By changing the environment temperature and changing the mass-to-volume ratio of the silk fibroin, the prepared absorbable orthopedic internal fixation material based on silk fibroin is more excellent in mechanical strength, good in biocompatibility, little in inflammatory reaction and convenient to implant, can realize autoclaved sterilization and fixation maintaining for 4-8 weeks, can reduce the stress shielding to the maximum extent, and has a wide application prospect.

The invention discloses a 3D-printed polyetheretherketone bone tissue symbiosis multihole skeleton substitute and a method thereof. The 3D-printed polyetheretherketone bone tissue symbiosis multiholeskeleton substitute comprises a bone tissue symbiosis region, wherein the bone tissue symbiosis region is a three-dimensional region where the bone substitute is in contact with bone tissue around thebone substitute and comprises a multihole region and an entity region, and the region except the bone tissue symbiosis region, in the substitute, is a bearing strengthening region. The problem that aPEEK material as a bone implant is difficult to be in symbiosis and combination with the bone tissue is solved, and the postoperative recovery of the PEEK bone implant is promoted.

The invention discloses a bone-grafting height-adjustable opening-type fusion cage. The bone-grafting height-adjustable opening-type fusion cage comprises a support, a sliding block and a supporting platform, wherein the first slant grooves are formed in the two sides of the back surface of the front end of the support, a positioning square groove is formed in top of the back end of the support, aguiding hole is formed in the back end in the horizontal direction, and a slant groove rail is arranged on the inner side face of the support; the sliding block is arranged on the front of the back end in the support, second slant grooves are formed in the two sides of the front end of the sliding block, the sliding block is in threaded connection with the back through a threaded rod, a limitinggroove corresponding to the positioning square groove is formed in a rod head of the threaded rod, and limiting plates are clamped into the limiting groove and the positioning square groove through the rod head of the threaded rod and are locked and connected with the support; the supporting platform comprises an upper supporting platform body and a lower supporting platform body, and the slidingblock moves for driving the upper supporting platform body and the lower supporting platform body to slide along the slant groove rail, the first slant grooves and the second slant grooves to achieveopening movement and closing movement of the supporting platform. The bone-grafting height-adjustable opening-type fusion cage is high in stability, and can adapt to adjustment of intervertebral spaceheights of different segments.

The invention provides a combined type full-organic polymer material artificial temporal-mandibular joint which comprises a temporal bone support fixed bone fracture plate made of polyether-ether-ketone (PEEK) or a derivative thereof, a condyle process head and a fixed bone fracture plate thereof which are made of PEEK or a derivative thereof, and a temporal bone lining made of ultra-high molecular weight polyethylene (UHMWPE), wherein the temporal bone support fixed bone fracture plate is matched with the upper part of the temporal bone lining, the lower part of the temporal bone lining is in a concave U-shaped sphere and is connected with the condyle process head and the fixed bone fracture plate thereof, the condyle process head has a buffer effect for the sliding face of the temporal bone lining, the temporal bone support fixed bone fracture plate can generate final motion on the fixed face of the temporal bone lining, and the temporal bone support fixed bone fracture plate and the temporal bone lining are matched with each other. According to the invention, the major parts of all the implanted parts are made of high polymer material, so that the problems of allergy and toxicity caused by metal and the corrosion thereof are solved; the elasticity modulus of PEEK is matched with that of the natural bone, so that the problem of stress shielding is solved; PEEK is in final motion match with the sliding surface and the fixed face of UHMWPE, so that the wear problem is greatly reduced; and meanwhile, enhancing and developing parts are added, so that the practicability is further improved.

The invention discloses an artificial hip joint thighbone end prosthesis which comprises a head ball, a full thighbone neck, a full hollow thighbone narrow cavity handle and a thighbone neck inner short handle, wherein the ball head is arranged on the upper end part of the full thighbone neck; the upper end of the full hollow thighbone narrow cavity handle is connected to the outer side of the bottom surface of the full thighbone neck; the thighbone neck inner short handle is arranged at the inner side of the bottom surface of the full thighbone neck; and the full hollow thighbone narrow cavity handle consists of a uniform cross-section tubular upper part and a swallow-tail form tubular lower part. The artificial hip joint thighbone end prosthesis utilizes the full hollow thighbone narrow cavity handle to replace a half hollow thighbone narrow cavity handle of the prior art , thus a swallow-tail form lower end on the full hollow thighbone narrow cavity handle can be inserted into a tubular bone area of a thighbone narrow cavity of a patient. Because the contact area of the full hollow thighbone narrow cavity handle and the thighbone narrow cavity is large and the full hollow thighbone narrow cavity handle is more deeply inserted into the thighbone narrow cavity, the stability of the prosthesis can be increased so as to prolong the service life of the prosthesis and reduce the overhaul rate and the pain of patients.

The invention discloses a novel automatic pressure locking steel plate. The automatic pressure locking steel plate particularly comprises a steel plate, a gasket, a buckle, a screw and a slidable hole; the slidable hole is formed in the steel plate, the slidable hole is used for being inserted by the screw, the gasket and the buckle are arranged between the screw and the slidable hole, the gasketand the buckle are in interference fit with the slidable hole, wherein the size of the slidable hole is 1.5-2 times that of the gasket, and the buckle is made of bioresorbable medical materials. The novel automatic pressure locking steel plate can automatically press a broken end of fracture, reduce stress shielding, facilitate the rapid formation of an osteotylus, and promote fracture healing.

The invention relates to an elastic spine fixing system and pressure-adjustable fixing rods for clinical application of a department of orthopedics. The elastic spine fixing system comprises any two of the pressure-adjustable fixing rods, two connecting cross rods (50), four fixed hooks (51) and a plurality of pedicle screws (46); each of the adjustable pressure fixing rods comprises an adjusting rod, a sliding fit thread sleeve, an elastic device and a fixed rod. The elastic spine fixing system and the pressure-adjustable fixing rods provided by the invention have the advantages that the pressure is adjustable, fixing is firm, the operation is simple, the adjustment is easy, stress shielding is effectively prevented, osteoporosis is avoided, and fracture healing is accelerated.

The invention discloses an implant for maxillofacial bone defect repair, and a preparation method of the implant. The implant structurally comprises a fixing unit and a porous structure part; the porous structure part is integrally connected with the fixing unit; the fixing unit comprises a screw hole and a first through hole; the fixing unit is matched with a healthy residual bone in shape; the porous structure part is located in the middle of the fixing unit and comprises a second through hole and an implant reserved socket; the porous structure part is filled in a maxillofacial disease bonearea or defect area; and the shape and size of the porous structure part are matched with the jaw anatomical structure of the maxillofacial disease bone area or defect area. According to the invention, personalized customization can be realized according to individual needs of patients; the implant is light in weight and low in material cost; meanwhile, the modulus of the implant is also reduced;therefore, the stress shielding effect caused by mismatching of the implant and the bone tissue modulus is avoided; the porous structure has the biological functions of promoting bone tissue ingrowth, vascularization and the like; and meanwhile, intraoperative bone grafting is carried out by reserving an implant alveolar socket, so that postoperative tooth implantation is facilitated.

A combined fully organic high molecular material artificial knee joint comprises a femoral condyle, a tibia bracket and a tibia pad; the femoral condyle and the tibia bracket are made of PEEK or derivatives of PEEK; the tibia pad is made of UHMWPE. The tibia bracket comprises a platform and a stable wing positioning portion perpendicular to the platform. The upper and lower ends of the tibia pad are combined with the femoral condyle and the platform respectively. The femoral condyle has a buffering function for the sliding face of the tibia pad. The tibia bracket can finely move relative to the fixed face of the tibia pad. The sliding face of the tibia pad relative to the femoral condyle is matched with fine motion of the tibia bracket relative to the tibia pad. The main parts of all implant components are made of high molecular materials, and the problems of irritability and virulence possibly caused by metal and corrosion of metal are solved. The elasticity modulus of the PEEK is matched with that of natural bones, and stress shielding is relieved. The sliding face and fixed face fine motion of the tibia pad made of UHMWPE from the femoral condyle and the tibia bracket made of the PEEK are combined, so that abrasion is greatly reduced. Meanwhile, enhancement and developing components are additionally arranged, so that the practicability is further improved.

The invention discloses an anterior cervical approach self-fixation artificial centrum and belongs to the technical field of medical centrum manufacturing. The anterior cervical approach self-fixationartificial centrum is composed of an integrated centrum part and is mainly characterized by comprising an upper-end cambered surface, a lower-end oblique plane, an end face sawtooth structure, an endface micro-hole structure, a side wall rhombus hole, a back wall micro-hole structure, a front wall cambered surface structure, a back wall cambered surface structure and a screw hole structure for front wall self-fixing. A traditional anterior cervical approach titanium plate is removed on the premise that the stability of postoperative spine segments is ensured, the complexity degree of sub-total ectomy fusion of an anterior cervical approach cervical vertebra body is effectively reduced, the surgical time is shortened, the bleeding during surgery is decreased, a biomechanical conduction mode of an anterior cervical approach implantation instrument is optimized, and lots of complications caused by anterior cervical approach steel sheets are avoided. By adopting the above design, the anterior cervical approach self-fixation artificial centrum can effectively decrease lots of complications of a traditional titanium cage and improves prognosis of a patient suffering from the sub-totalectomy fusion of the anterior cervical approach cervical vertebra body.

The invention discloses a 3D-printed short implant with a gradient and porous outer layer and a preparation method for the 3D-printed short implant. The short implant is used for being implanted into an alveolar bone implantation pit of a sufferer and comprises a head part and a somatic part connected with the bottom surface of the head part; the somatic part comprises a dense core and a porous layer arranged outside the dense core; the porous layer has pores; along a direction from the dense core to an alveolar bone, the porosity of the porous layer is improved gradually, and the elastic modulus of the porous layer is decreased gradually from that close to or equal to that of the dense core; and the global mean modulus of elasticity of the porous layer is the same as the mean bone modulus of elasticity of the sufferer. The short implant is prepared through integrated molding by a 3D printing technology; and due to the porous layer, the bone binding area is increased, the binding between the short implant and the alveolar bone is facilitated, the long-term stability of the short implant is facilitated, and more loads can be born even if the height of the alveolar bone is insufficient. Simultaneously, the porous layer can load drugs to induce rapid growth of bone tissue, and the short implant is applied to hypodontia-suffered sufferers with insufficient bone mass of upper and lower molar regions.

The invention provides a nonmetallic implant screw locking structure which is simple in structure, novel in design, simple to produce and very convenient to clinically operate. The nonmetallic implantscrew locking structure is applicable to traumatic bone plates, spinal fusion cages, spinal fixing plates, cervical posterior single-opening door plates, cervical posterior plates, lumbar anterior plates, lumbosacral plates and other nonmetallic implants, and good economic and social benefits can be created gradually.

The invention relates to an elastic internal fixing system and a pressure-adjustable fixing rod for clinical application of a department of orthopedics. The one or two pressure-adjustable fixing rods are adopted and form the elastic internal fixing system with more than two single rod type and double rod type or anatomical nail fixing devices. The pressure-adjustable fixing rod comprises an adjusting rod, a sliding fit thread sleeve, an elastic device and a fixed rod. The elastic spine fixing system and the pressure-adjustable fixing rod provided by the invention have the advantages that the pressure is adjustable, fixing is firm, the operation is simple, the adjustment is easy, stress shielding is effectively prevented, osteoporosis is avoided, and fracture healing is accelerated.

The invention is a facet fusion with annular hollow cylinder figuration. Wherein, the side wall of the cylinder has an opening, the upside surface and the down-side surface have antiskid superficial structure, and the shape is near to the upside and down-side end-plate. The optimization plan is the annular hollow rectangular cylinder, and the transverse section exposes mouth shape. The invention has the effect of stability and lasting support, meanwhile the bone transplantation area and the bone transplantation quantity is twice than the normal structure, to increase the fusion ratio of the bone transplantation substantially, and to eliminate the problems to some essence such as depression after implantation as well as the intervertebral high lost. In addition, the invention provides a propulsion to push the facet fusion into the intervertebral space.

A combined organic polymer material artificial knee joint, including femoral condyle and tibial support of polyetheretherketone (PEEK) or its derivatives and tibial liner of ultra-high molecular weight polyethylene (UHMWPE), wherein the tibial support includes a platform and The positioning part of the stabilizer wing perpendicular to it; the upper end and the lower end of the tibial liner are respectively engaged with the femoral condyle and the platform; the femoral condyle has a buffer for the sliding surface of the tibial liner; The sliding surface against the tibial liner matches the fretting of the tibial tray against the tibial liner. The main parts of all implant parts of the present invention are made of polymer materials, which reduces the allergies and toxicity problems that metals and their corrosion may cause; the elastic modulus of PEEK matches the natural bone, which reduces the stress shielding problem; the PEEK femoral condyle and The tibial tray combines the sliding surface and the fixed surface of the UHMWPE tibial liner with micro-movement, which greatly reduces the wear problem. At the same time, the reinforcement and development parts are added to further improve the practicality.

Disclosed herein are flexible prosthetic components that are designed to be snap-fit to bone of a patient. The prosthetic components each have an outer articular surface and an inner bone contacting surface opposing the outer articular surface. The bone contacting surface has an anterior surface and an opposing posterior surface configured to contact corresponding anterior and posterior surfaces of the patient's bone. At least one of the anterior and posterior surfaces includes one or more protrusions extending outwardly therefrom. The anterior and posterior surfaces of the prosthetic components may flex toward and away from one another such that the one or more protrusions may snap-fit into corresponding recesses in the bone. The bone of the patient may be resected to include planar surfaces or resurfaced to include a curved surface corresponding to the respective bone contacting surface of the prosthetic components.

The invention discloses an artificial joint femoral stem and a preparation method thereof. The preparation method includes the steps: firstly, forming a hole or a groove in an artificial joint femoral stem body by the aid of various processing methods; secondly, building a cylindrical projection, a spherical projection or other stereoscopic shapes in the hole or the groove by the aid of additional material manufacturing technologies. A locking function is formed among an implant and bone tissues, ideal space structures for growing new bones can be provided, attachment and proliferation abilities of bone tissue cells are improved, excellent bone combination is achieved, convergence among the artificial joint femoral stem and autologous tissues is improved, and the artificial joint femoral stem effectively plays a role in a human body for a long time, is excellent in mechanical property and high in mechanical strength, can effectively reduce stress shielding and keep effective mechanical support.

The invention discloses an artificial joint femoral stem and a preparation method thereof. The preparation method includes the steps: firstly, forming a hole or a groove in an artificial joint femoral stem body by the aid of various processing methods; secondly, building a cylindrical projection, a spherical projection or other stereoscopic shapes in the hole or the groove by the aid of additional material manufacturing technologies. A locking function is formed among an implant and bone tissues, ideal space structures for growing new bones can be provided, attachment and proliferation abilities of bone tissue cells are improved, excellent bone combination is achieved, convergence among the artificial joint femoral stem and autologous tissues is improved, and the artificial joint femoral stem effectively plays a role in a human body for a long time, is excellent in mechanical property and high in mechanical strength, can effectively reduce stress shielding and keep effective mechanical support.

The invention discloses a dental implant preparation method. The method comprises the following steps: firstly, forming a hole or a groove in a dental implant body by the aid of various processing methods; secondly, building a cylindrical projection, a spherical projection or other stereoscopic shapes in the hole or the groove by the aid of additional material manufacturing technologies. A locking function is formed among an implant and bone tissues, the ideal space structures for growing new bones can be provided, attachment and proliferation abilities of bone tissue cells are improved, excellent bone combination is achieved, convergence among the dental implant and autologous tissues is improved, and the dental implant effectively plays a role in a human body for a long time, is excellent in mechanical property and high in mechanical strength, can effectively reduce stress shielding and keep effective mechanical support.

A combined all-organic macromolecule material artificial temporomandibular joint, including polyetheretherketone (PEEK) or its derivatives temporal bone plate, condylar head and its fixed bone plate, and ultra-high molecular weight polyethylene (UHMWPE) Temporal bone lining, in which the fixed bone plate of the temporal bone tray matches the upper part of the temporal bone lining, and the lower part of the temporal bone lining has a concave U-shaped spherical surface and is connected with the condylar head and its fixed bone plate; the sliding surface of the condylar head on the temporal bone lining has a Cushioning, the fixed surface of the temporal bone support plate and the temporal bone lining can be slightly moved, and the two match. The main parts of all implant parts in the present invention are composed of polymer materials, which reduces the allergies and toxicity problems that may be caused by metals and their corrosion; the elastic modulus of PEEK matches the natural bone, which reduces the problem of stress shielding; the sliding of PEEK to UHMWPE The micro-movement combination of the surface and the fixed surface greatly reduces the wear problem, and at the same time, the reinforcement and development parts are added to further improve the practicability.