1314 results about "Modular construction" patented technology

The present invention relates to an adaptive manufacturing method for building components, particularly in prefabrication, modular construction, and panelized construction. The invention minimizes cumulative errors in building component production, enhances precision, and facilitates automated assembly using real-time digital updates. The method includes creating a digital information model of a building, containing data on the dimensions and positions of building components; manufacturing at least one building component based on initial model parameters; scanning the manufactured component using laser scanning, structured light scanning, or ultrasound-based scanning, selected based on the material properties, to generate a digital representation of its actual dimensions and shape; updating the digital model with the scanned data to dynamically adjust parameters for subsequent components; recalculating and adjusting the parameters of unmanufactured components based on detected deviations; transmitting adjusted parameters to an automated manufacturing system for real-time modifications in production. The system comprises a processor executing adaptive manufacturing instructions, a scanning module, a processing unit, and a recalculation module that updates component dimensions based on deviations, ensuring seamless integration of prefabricated elements.

A modular, multi-directional, smart electric vehicle (EV) charging station. In an embodiment, the EV charging station has a field-serviceable, replaceable modular construction, a fully multi-directional power routing architecture, buffered EV-to-grid and EV-to-EV charging, multi-EV charging capability, and the ability to integrate multiple modular charging stations into a networked local and / or wide-area charging system.

The invention discloses an active prediction type modular battery thermal management system, which comprises the following steps: a liquid path and electrical connection module, a data acquisition module, a communication transmission module, a working condition identification module, a feedback control module, a cooperative control module, an execution adjustment module, a state feedback module, an exception handling module, a redundancy switching module and the like. A prediction control instruction is generated by combining a working condition recognition result, a fusion control quantity is formed by the prediction control instruction and temperature feedback, amplitude limiting control is conducted according to thermal power evaluation and a set threshold value, coordinated adjustment of a pump, a valve and a bypass assembly is achieved, and if recognition fails or data is abnormal, the system automatically freezes prediction control and executes closed-loop adjustment only depending on feedback. And the standby device takes over the fault after fault judgment, so that continuous operation and safety maintenance of the system are guaranteed. The system has a modular structure and complete maintenance process support.

The invention discloses a ship block modular design construction precision control method and device, and relates to the technical field of ship construction, and the method comprises the steps: building a size chain relation of all parts in a preset module according to ship block modular construction standard data; establishing a three-dimensional assembly model of the preset module based on the dimension chain relationship, and establishing a three-dimensional assembly deviation analysis model according to the three-dimensional assembly model; solving a closed ring out-of-tolerance rate and a composition ring influence weight according to the three-dimensional assembly deviation analysis model; determining whether a simulation result meets a preset requirement or not according to the closed ring out-of-tolerance rate and the component ring influence weight; when the simulation result meets a preset requirement, establishing an out-of-tolerance rate comprehensive evaluation model according to the simulation result; the influence coefficient of each composition ring on the overall out-of-tolerance rate is solved according to the out-of-tolerance rate comprehensive evaluation model; and determining a construction precision control scheme according to the influence coefficient, and performing ship block modular construction precision control according to the construction precision control scheme.

The invention relates to the technical field of flat car bearing, in particular to a flat car grid-shaped anti-skid platform structure which is of a modular structure, each modular anti-skid platform structure comprises a frame and a grid-shaped supporting component, the grid-shaped supporting components are arranged in the frames to form a plurality of supporting inner grids, and the grid-shaped supporting inner grids are arranged in the frame. The anti-skid components are arranged in the supporting inner grids; the anti-skid component is made of a deformation material, and the upper surface of the anti-skid component is higher than the upper surface of the grid-shaped supporting component, so that the anti-skid component wraps crawler teeth of crawler-type equipment borne by the platform; the grid-shaped supporting component is made of a rigid material so as to form rigid supporting limiting on the crawler teeth and limit the cutting degree of the crawler teeth to the anti-skid component. The platform has the advantages that the platform is antiskid and durable, the lightweight process is realized, the load of the platform is uniform, the service life is long, transverse sliding is effectively resisted, the maintenance cost is low, the modular design supports local replacement, the antiskid material is durable and low in cost, and the long-term maintenance expenditure is reduced.

The invention discloses a bridge deck system multi-sub-project integrated construction process optimization method. The method comprises the following steps: step 1, optimizing a process based on a BIM (Building Information Modeling); step 2, carrying out combined measurement by adopting GNSS-RTK and laser scanning; 3, bridge deck pavement construction and expansion joint installation are conducted on the basis of the combined measurement result; 4, the paver is linked with the reserved groove for positioning, the flatness error can be effectively controlled, and the bridge deck pavement quality is guaranteed; 5, guardrail modular construction is carried out; sixthly, seamless connection, layered backfilling and dynamic compaction are conducted on the butt strap behind the abutment; 7, whole-process environmental protection and finished product protection; 8, performing three-dimensional scanning comparison; step 9, block chain data archiving; the method has the beneficial effects that construction simulation, sequence adjustment and dynamic monitoring are carried out based on the model optimization process logic, the problems of process crossing and construction period conflict can be recognized and eliminated by simulating the construction process in advance, accurate positioning of each subentry project is ensured, and the overall coordination of construction is improved.

To provide a wiring structure for a hub motor in which wiring connection parts are formed into a modular structure, assembly strength and alignment precision are improved, and assembly can be made easier during installation. [Solution] The wiring structure for a hub motor comprises a hub motor and a wiring unit 10, the wiring unit having a motor connection section 20 and a wire connection section 30, with a load terminal wiring board 25 of the motor connection section and a power supply end wiring board 36 of the wire connection section interconnected by a plurality of bridge connecting rods 24 to form a modular structure. This effectively improves assembly strength and alignment accuracy, makes assembly easier during installation, and more effectively increases safety in use while reducing the overall volume of the wiring unit.

The invention discloses a hot melting forming device and method for a synthetic quartz glass cylinder, through modular structural design, the synergistic effect of positioning, exhausting, pressing and forming is achieved, and the hot melting forming device for the synthetic quartz glass cylinder specifically comprises a graphite pressure head connecting rod, a graphite pressure head, a graphite center rod and a forming mold. According to the hot-melting forming method for the synthetic quartz glass cylinder, the device is adopted, a synthetic quartz glass ingot is pretreated, a low-impurity demolding material is laid during assembling, gradient heating is conducted on three temperature areas of a heating furnace, pressurization is conducted after softening, and then differential cooling is conducted, so that efficient preparation of the high-purity synthetic quartz glass cylinder is achieved; and the purity of the finished product meets the strict requirements of high-precision processes such as semiconductor wafer processing and thin film deposition on the material purity. According to the invention, the large-diameter and ultra-long synthetic quartz glass cylinder can be stably produced, the requirement of large-size development of semiconductor equipment is met, and the blank in the field of large-size high-purity quartz glass cylinder preparation in the prior art is filled.

A stator structure of a magnetic levitation flux-switching motor includes a stator of a modular structure and a motor housing. A modular stator includes front and rear side winding end heat dissipation modules, modular stator left and right wings, a modular stator permanent magnet, front side magnetic conduction column left and right wings, an inter-front side and inter-rear side magnetic conduction column permanent magnets, insulating layers, a stator winding, and rear side magnetic conduction column right and left wings. The front side and rear side winding end heat dissipation modules are of hollow structures, and are symmetrically provided with a cooling medium inlet and a cooling medium outlet, a cooling medium channel is disposed inside a hollow cavity, one side of the heat dissipation module is a smooth curved surface, and good thermal contact can be achieved between the heat dissipation module and the stator winding and the insulating layer.

The invention discloses a test device and a test method for a vibration and dislocation double-input lower span tilting-sliding fault tunnel. The test device comprises a test box body, a hydraulic actuator, a loading unit, a covering layer soil body, a tunnel physical model and a sensor monitoring system, wherein the test box body consists of a movable steel plate and a fixed steel plate; the loading unit consists of an angle adjusting module and a hydraulic control system; a bed rock model, a covering layer soil body and a tunnel model are arranged through a modular construction method, and data are collected in real time through soil pressure, microseismic and strain sensors and displacement meters. According to the invention, the failure mechanism of the cross-fault tunnel under the coupling action of bed rock dislocation and pulse seismic oscillation can be accurately simulated, the damage rule of the combined action of fault dislocation and seismic waves to the tunnel structure is revealed by qualitatively and quantitatively analyzing the strain, displacement, soil pressure and seismic oscillation response of the tunnel, and a test basis is provided for the aseismic design of the cross-fault tunnel.

A modular construction housing system includes fiber-reinforced wall panels, such as fiberglass wall panels, attached to a roof component via one or more pins extending downwardly from the roof component into an internal cavity of the wall panels. The wall panels and the flooring of the modular construction housing system are integrally formed via molding to reduce the number of separate components and the amount of construction and connection required on-site. The wall panels include a plurality of internal conduits extending through the internal cavity of the wall panels configured to align with internal conduits extending downward from the roof component to allow for electrical wiring and other function to seamlessly extend from the wall to the roof.

The invention discloses an assembly type building stair mold, and relates to the technical field of stair molds, the assembly type building stair mold comprises a mold mechanism, the side face of the mold mechanism is provided with a transverse steel bar limiting mechanism, and the transverse steel bar limiting mechanism is used for limiting and fixing transverse steel bars in a prefabricated stair. According to the longitudinal reinforcement limiting mechanism, the height of a clamping head is accurately adjusted through a third mounting bolt, the clamping head can be flexibly selected according to the diameter of a longitudinal reinforcement, the mounting height and position of the longitudinal reinforcement can be accurately controlled, the overall positioning accuracy of a reinforcement framework is guaranteed, and then the mechanical property of the prefabricated stair is improved; the sleeve plays a role in protecting the end, inserted into the mold mechanism, of the third mounting bolt, it is avoided that concrete adhesion affects bolt disassembly, meanwhile, due to the detachable design of the third mounting bolt and the modular structure of the steel bar limiting mechanism, the demolding difficulty is lowered, damage to stairs after a component is formed is reduced, and the demolding efficiency and the finished product quality are improved.

A construction system motor unit comprising a casing, an electrical motor mounted therein, a power outtake element having a connector, and being rotationally connected relative to said casing, a gearing mechanism provided between the electrical motor and the power outtake element, and a sensor to sense the position of the power outtake element relative to the casing, the sensor having a disc element and a sensor device, the disc element is connected to the power outtake element or to a gear of the gearing mechanism via a first rotation transfer part and a receptacle for receiving the first rotation transfer part, which receptacle is formed in the power outtake element or in said gear of the gear mechanism, and wherein the receptacle and the first rotation transfer part have cooperating shapes and sizes configured to allow a backlash between the power outtake element and the first rotation transfer part.

An assembly type vehicle is configured not only to simplify an assembly process by enabling assembly of each portion through a sliding assembly structure, but also to enable manufacture of a vehicle tailored to meet diverse needs of users through a modular structure, securing assembly performance and productivity of the vehicle.

The invention discloses an underground powerhouse composite aluminum plate modular construction system and method, belongs to the technical field of underground building decoration, and solves the problems that in traditional underground powerhouse decoration, aluminum plates crack due to rock wall deformation, and the construction precision is difficult to guarantee. According to the technical scheme, the modular composite aluminum plate unit is composed of a light keel frame, a filling layer and a decorative aluminum plate layer, and an independent supporting structure is formed through rigid connection of an integral keel net and a generator layer concrete constructional column; the flexible telescopic device is arranged in a gap between the keel net and the rock wall in an embedded mode. And the digital dynamic control module monitors flatness and deformation data in real time through a laser range finder and a vibration sensor, and automatically adjusts the displacement of the inclined long hole of the connecting corner brace and the pre-tightening force of the expansion bolt by using an intelligent feedback actuator. The system is mainly used for high-precision modular decoration construction of an underground powerhouse generator layer, and can effectively adapt to rock wall deformation and ensure that the construction quality is stable and reliable.

Provided is a three-dimensional truss optimal designing and manufacturing method based on relaxed modular constraint. The method includes the following steps: initial design layout optimization, cluster analysis identification module arrangement, relaxed modular constraint design, geometric optimization, and 3D printing manufacturing and integrated assembly. The method has the following beneficial effect. A three-dimensional truss structure containing various module types is automatically designed by an iterative method. In the iterative process, a cluster analysis method is introduced to identify the module arrangement. By applying relaxed modular constraints, an optimized solution is gradually pushed to the modular structure. The optimization results of the three-dimensional truss have the characteristics of various types of modular structures, which is relatively easy to manufacture. An iterative solution method of cluster analysis identification module arrangement and relaxed modular constraint design is proposed.

The invention provides a leading pretreatment device for pumping and cleaning clustered marine organisms and floaters, the leading pretreatment device comprises a buoyancy platform, a butt joint structure, a controller and a dispersion assembly, a treatment cabin is arranged in the middle of the buoyancy platform, and the dispersion assembly is composed of a turbulent flow triggering assembly and a liquid spraying assembly; impurities are collected in a suction mode, the device is provided with self-buoyancy and a modular structure and can be rapidly in butt joint with a tail bag of an interception net, the optimal suction posture is achieved, and the core innovation of the device is that a dispersing assembly and a cutting device are sequentially arranged in the suction direction, material distribution is achieved through a rotating cylinder and a conical column, and high-frequency vibration and a reverse micro-impact mechanism are combined; the block mass structure is effectively damaged; by adopting the unique design of the fixed impeller and the rotary volute, an annular liquid curtain is formed when the barrel rotates, so that the winding property and the overall strength of disaster-causing objects can be reduced, the disaster-causing objects are more easily scattered and cut by subsequent components, the subsequent mechanical load is reduced, the problem of blockage of a flow channel is solved, and the energy consumption and the abrasion of equipment are reduced.

A fastening arrangement of a seat on a rail arrangement may have a modular construction and may have one lock module for releasably arresting the fastening arrangement on the rail arrangement. The fastening arrangement may also have one lock unlocking module for unlocking the lock module. The fastening arrangement may also have one rail unlocking module.

The invention relates to the technical field of check valves, in particular to a butterfly check valve with opening indication, which comprises a valve body, a transmission gear and a frame body are respectively arranged on the surface and the top of a right-angle part of an L-shaped mounting groove of the valve body, and a screw rod transmission mechanism on the inner wall of the frame body is respectively connected with the transmission gear and a strip-shaped sliding seat which is horizontally and slidably connected to the top of the frame body; a mechanical opening indicating mechanism; and a sensing indication mechanism is integrated. Opening, flow, pressure and sealing states can be detected synchronously, mechanical indication and electronic sensing are combined, electricity-free use and digital reading are both considered, and misjudgment is reduced through the multi-redundancy design; the transparent observation plate and the modular structure are convenient to operate and maintain, and the liquid collection and drainage design prevents interference of condensate water; the flowmeter wear-resistant ceramic probe and the pressure sensor moisture-proof shell are adaptive to complex working conditions; backflow can be effectively recognized through bidirectional flow detection and triple sealing verification, the safety redundancy of a system is greatly improved, and the problems that a traditional check valve is single in function and insufficient in reliability are solved.

The invention provides a building electromechanical pipeline modular construction method based on the BIM technology, and relates to the technical field of BIM. The method comprises the steps that comprehensive arrangement of project pipelines is conducted through the BIM technology, adjustment is conducted according to cross collision occurring in the installation process, a support is designed, and support stress is rechecked; the method comprises the following steps of: designing a comprehensive pipeline of a region in BIM software in detail according to nodes, dividing the comprehensive pipeline into electromechanical pipeline installation modules of one unit, and providing a pipeline module three-view; module prefabrication is conducted according to the requirements of a BIM module drawing, after prefabrication is completed, segmented comprehensive electromechanical pipelines are assembled on a manufactured assembly frame, and transportation is conducted after assembly; and an overall installation scheme is planned according to the overall pipeline installation area, the bearing capacity of a floor or a beam is rechecked, and segmented hoisting or lifting and overall module splicing of the pipeline unit modules are carried out. The comprehensive quality and construction safety of the electromechanical pipeline system are improved.

A modular structural element (20) which is arranged to be connected to another such element so as to form an assembled structure, wherein the modular structural element is of substantially square outline or of substantially hexagonal or half-hexagonal outline, and the element comprises a principal height dimension and a principle lateral dimension, wherein, a ratio of the two said principal dimensions is no more than 6.

The invention discloses a modular assembly type hydraulic jacking portal crane which comprises a rail device, a hydraulic jacking device and a hydraulic jacking device. The number of the walking devices is two, the walking devices are movably arranged on the left track and the right track respectively, each walking device comprises a power unit and a walking vehicle, and the power units are connected to the walking vehicles in a replaceable mode and used for driving the walking vehicles to move along the track devices; the supporting device is detachably arranged on the walking vehicle; the cross beam is detachably arranged on the supporting device; wherein the rail device, the walking device, the supporting device and the cross beam are all of modular structures and can be adaptively adjusted and assembled according to needs, and the driving friction force of the power unit relative to the rail device can be adjusted. The crane can efficiently and conveniently complete manual installation, hoisting operation and disassembly transition in a high-floor room and other scenes with limited space, the driving friction force can be accurately and efficiently adjusted, and efficient and safe load hoisting can be achieved.

The invention relates to the technical field of bridge high pier construction, in particular to a bridge high pier construction system and method based on multistage hydraulic synchronous climbing formworks. The system comprises a formwork unit, a support unit and a hydraulic driving unit, and overall synchronous climbing of the formwork unit and the support unit is achieved through cooperative driving of a hydraulic cylinder, an upper reversing box and a lower reversing box; the high-altitude operation risk that formworks need to be disassembled and assembled repeatedly in traditional formwork overturning is avoided, and the construction safety is remarkably improved; the detachable design of the guide rail and the wall-attached bearing device is matched with the multi-platform structure of the bearing tripod, the backward moving mechanism, the middle platform and the lifting platform to form a modular construction system, materials can be rapidly turned over, and the single-time construction period is shortened; meanwhile, manual and mechanical investment is reduced through the system integrated design, continuous operation can be achieved in cooperation with the layered pouring process, the comprehensive efficiency is improved by 40% or above compared with a traditional method, and economic benefits and construction quality controllability are remarkably improved while the safety cost is reduced.

The invention discloses a longitudinal bending composite type six-degree-of-freedom piezoelectric active vibration isolation platform and a working method thereof. The vibration isolation platform adopts a modular structural design, a vibration isolation connecting platform and a base platform are sequentially arranged from top to bottom and are connected through four uniformly distributed vibration isolation modules, and each vibration isolation module forms a multi-stage vibration transmission structure through a fixed base, a transducer base, a piezoelectric transducer, an amplitude-change pole, a pre-tightening bolt and a small flexible hinge. The control module collects feedback signals of a first acceleration sensor arranged on the vibration isolation connecting platform and feedforward signals of a second acceleration sensor arranged on the base platform, and outputs 12-channel control signals to the piezoelectric transducers of the vibration isolation modules after signal processing. The piezoelectric transducer is driven to generate a composite motion mode of longitudinal vibration and multidirectional bending vibration, and active suppression of longitudinal vibration and radial bending vibration in any direction of a vibration isolation object is achieved. The device has the advantages of multi-degree-of-freedom vibration isolation, compact structure, lightweight design, independent control, high stability and the like, and has important application value in the fields of space reflecting mirrors, micro-nano manufacturing equipment vibration control and multi-degree-of-freedom vibration isolation systems.

The invention relates to the technical field of food processing equipment, in particular to an intelligent pastry continuous leavening and steaming system which comprises a leavening mechanism and a steaming mechanism and further comprises a conveying assembly, a steam supply system and a control system. The conveying assembly penetrates through the leavening mechanism and the steaming mechanism and is used for sequentially conveying pastries into the leavening mechanism to finish leavening and conveying the pastries into the steaming mechanism to finish steaming, and the leavening mechanism and the steaming mechanism are each of a modular structure and are composed of a plurality of independent leavening units or steaming units which are in butt joint front and back; a liftable fermentation section upper cover device is arranged at the top of the fermentation mechanism, a liftable steaming section upper cover device is arranged at the top of the steaming mechanism, the fermentation section upper cover device and the steaming section upper cover device are each provided with a drainage structure, and each drainage structure comprises a flow guide plate and a collecting groove; the control system is electrically connected with the leavening mechanism, the steaming mechanism, the conveying assembly and the steam supply system. The pastry food leavening and steaming device can improve the leavening and steaming efficiency of pastry food.

A wireless network, systems and methods, wherein each passenger-carrying rideable vehicle deployed in the system includes: a modular construction consisting of a lightweight body driven by an electric-battery driven motor, and specially adapted for receiving a customizable ornamental body having the appearance and personality of a particular or an inanimate object; motorized and / or animated elements disposed beneath the animal character skin covering for enabling animal behaviors and / or expressions that promote a fun and entertaining ride experience; an audio-transducers mounted within the animal character body for playing music from smartphone applications and animated animal character body portions to provide a sense of realism and excitement as the electric entertainment vehicle is ridden through an amusement facility.

The invention discloses a five-axis linkage 3D printer with double forming modes and a printing forming method of the five-axis linkage 3D printer. The five-axis linkage 3D printer comprises a frame supporting structure, a planar motion structure, a printing nozzle assembly, a U-axis swinging structure and a V-axis rotating structure. The frame supporting structure is used for installing the printing nozzle assembly and the planar motion structure. The planar motion structure is used for mounting the U-axis swinging structure and the V-axis rotating structure; a plane printing platform and a detachable tubular printing rotating table are arranged on the V-axis rotating structure; the plane printing platform and the tubular printing rotary table are used for plane printing and tubular printing correspondingly. By means of the design of the detachable tubular base body, five-axis linkage forming methods of different types can be rapidly achieved, the unique modular structure enables single equipment to have the dual functions of special tubular printing and universal five-axis forming, and efficient integration of special tubular printing and universal five-axis forming is achieved.

The invention relates to the technical field of refrigeration equipment, and discloses a refrigerator which comprises a refrigerator body, a door body and an ice maker. The box body comprises a box shell and an inner container, and a refrigeration cavity is formed in the inner container; the ice maker is arranged in the refrigeration chamber; the ice maker comprises a water injection unit, a rack and ice cube trays, the water injection unit is connected with the inner container, the rack is mounted on the water injection unit, and the ice cube tray is hinged in the rack; wherein the water injection unit comprises an end cover and a water injection pipe; the number of the end covers is at least two, the end covers are sequentially arranged on the inner container, and every two adjacent end covers are detachably connected. The water injection pipes and the end covers are arranged in the same number, and the water injection pipes are connected with the end covers in a one-to-one correspondence mode. By arranging the end covers which are detachably connected, the water injection pipes are connected with the end covers in a one-to-one correspondence mode, the modular structural design of the water injection units is achieved, the end covers of the water injection units of different specifications can be commonly used, the specification structures of the end covers can be subjected to unified batch production, and then the production cost is reduced.

The invention is suitable for the field of portal frames, and discloses a portal frame dynamics analysis method which comprises the following steps: establishing a full-order finite element model of a portal frame, and obtaining a mass matrix and a stiffness matrix of the full-order finite element model; dividing the full-order finite element model into a plurality of substructures based on the modular structure characteristics of the portal frame, and decomposing the degree of freedom of each substructure into an internal degree of freedom and a boundary degree of freedom; constructing a fixed boundary main modal matrix and a constraint modal matrix of each substructure, and constructing a reduced-order basis matrix; performing modal polycondensation on a mass matrix and a stiffness matrix of the full-order finite element model by using the reduced-order basis matrix to generate a reduced-order mass matrix and a reduced-order stiffness matrix, and constructing a reduced-order kinetic equation; and solving the reduced-order kinetic equation to obtain reduced-order modal coordinates, carrying out inversion reduction in combination with the reduced-order basis matrix and the reduced-order modal coordinates to obtain a displacement response vector of the full-order finite element model, and retaining key kinetic information of the portal frame to the greatest extent through reduced-order efficiency improvement.

The invention relates to the technical field of heat exchangers, in particular to an axial tube plate module combined heat exchanger and a working method.The heat exchanger comprises two end sockets, a plurality of axial tube plate modules sequentially arranged in series, a first medium inlet, a first medium outlet, a second medium inlet and a second medium outlet, the axial tube plate module comprises a shell, two vertical tube plates arranged in parallel in the axial direction of the shell and a plurality of first heat exchange tubes penetrating through the vertical tube plates, the shell is divided into a middle shell pass cavity and two side tube pass cavities through the two vertical tube plates, partition plates are arranged at the ends of the tube pass cavities, and communicating holes are formed in part of the partition plates, so that shell pass flow channels are sequentially communicated in the multiple modules. Forming a serpentine flow path of the first medium; the shell pass cavities of the adjacent modules communicate with each other to form a second medium flow channel, each axial tube plate module is equivalent to an independent heat exchange unit, multi-stage heat exchange is achieved in a single device through a modular structure, multiple devices and external pipelines are not needed, the heat exchange efficiency is remarkably improved, and the structure is simplified.