218results about How to "Guaranteed lightweight" patented technology

The invention belongs to the field of polypropylene modification, and particularly relates to a polypropylene composition and a preparation method thereof. The polypropylene composition provided by the invention is prepared from the following raw materials in parts by weight: 100 parts of polypropylene resin, 0.05-2% of heat stabilizer, 0.02-0.5 part of stearic acid metal salt, 0.05-3 parts of inorganic filler and 0.01-0.2 part of organic nucleating agent. The polypropylene resin composition, which is prepared by blending and granulating the polypropylene resin, heat stabilizer, stearic acid metal salt, inorganic filler and slight nucleating agent, has the advantages of high rigidity, high heat resistance and low cost; the preparation technique is simple and easy to implement; and the polypropylene resin composition can be used in the fields of automobiles, home appliances, home furnishing and the like.

A process for preparing carbon fiber screening paper is provided. The invention includes the following steps: mixing chopped carbon fiber and plant carbon fiber in a certain proportion, adding certain amounts of a dispersant and a defoaming agent, dispersing on a fluffer, and papermaking in a paper former. While the light weight of material is guaranteed, the paper is endowed with good screening performance and easy process, which make full use of the advantages of large scale production in the papermaking industry. Furthermore, the paper electric conductive screening performance can be controlled by adjusting and quantifying the amount of the carbon fiber. The carbon fiber screening paper, which is an electric conductive material with high performance, replaces the conventional electric conductive screening material and covers the shortages thereof. The prepared screening paper has good screening performance of electromagnetic waves, the screening effectiveness at 100KHz-1500MHz is more than 30dB and the maximum is 50dB, thereby being generally applicable to radiation protection and anti-interference of common commercial or electronic products.

A high-precision semantic search system oriented to the judicial field comprises a data layer, a word analysis layer, a sentence analysis layer, a sentence feature layer and an application layer, andthe data layer comprises data acquisition and structuralization and is used for collecting judicial data and structuralized data; the word analysis layer comprises fine-grained word segmentation and new word discovery, and is used for realizing correct segmentation of the text into words; the sentence analysis layer is used for performing part-of-speech analysis based on the segmented words, removing interference words according to a judicial scene, further extracting keywords of sentences and establishing a key vocabulary; the sentence feature layer is used for extracting sentence features; and the application layer is used for defining correlation based on the sentence features to realize text search.

The invention provides a wearable vital sign monitoring device and a mental status monitoring method. The wearable vital sign monitoring device comprises two parts, namely a wearable multi-sign acquiring device and a server, wherein the wearable multi-sign acquiring device consists of a vital sign acquiring module and a processing and communicating module; acquisition of different physiological signals is realized by the vital sign acquiring module; the physiological signals are processed and integrated by an embedded lower-power-consumption processor, then are transmitted to a server side by the communicating module in a wireless mode and are stored and processed in the server; the mental status monitoring method provides a method for evaluating a mental status on the basis of sign signal data. According to the wearable vital sign monitoring device and the mental status monitoring method provided by the invention, by combining with a flexible processing technique and using a textile electrode, leads and various textile sensors embedded into clothes, lightness and comfortableness of the device are ensured while multiple physiological parameters are acquired; further analysis, exploitation and utilization of the acquired sign parameters are realized, and real-time judgment and early warning of a body and the mental status are realized.

The invention discloses a rail vehicle body which is low in weight and renewable in resource, preserves heat and lowers noise. The rail vehicle body comprises a roof, end walls, a side wall and a bottom frame. The bottom frame comprises a bottom plate and a bearing structure. A vehicle main body is defined by the side wall, the roof and the bottom plate. The side wall and the roof are in fillet transition, the side wall and the bottom plate are in fillet transition, the vehicle main body is integrally formed by winding bamboo skin and resin, the end walls are fixed to the ends of the vehicle main body, and the vehicle main body is fixed to the bearing structure. The invention further discloses a preparation method of the rail vehicle body. The preparation method includes the steps of resin modification, wherein modifier and flame retardant are added to the resin; bamboo skin pretreatment, wherein the bamboo skin is subjected to water removal and antiseptic treatment, and then the bamboo skin is connected into a continuous bamboo skin belt; manufacturing of a mandrel; vehicle main body winding, wherein the bamboo skin belt winds around a mandrel in a transverse, longitudinal and spiral intersecting mode, and the modified resin is poured during winding; manufacturing of the end walls and the bearing structure; fixation of the end walls to the ends of the vehicle main body; fixation of the vehicle main body to the bearing structure.

The invention relates to an all-water foaming cold-cure foam fireproof sealant and a preparation method thereof and belongs to the technical field of fireproof sealing materials. The all-water foaming cold-cure foam fireproof sealant is prepared from 100 parts of polylol, 38-50 parts of a liquid-state phosphate fire retardant, 110-120 parts of a powdered fire retardant, 2-5 parts of pigments, 1.8-4 parts of de-ionized water, 0.5-1.8 parts of a tertiary amine catalyst, 1.8-2.4 parts of an anti-hydrolysis temperature-sensitive catalyst, 1.8-2.5 parts of a chain extender, 0.4-0.6 part of high-activity silicone oil, 2.76-11 parts of a catalytic activation agent, 0.8-1.8 parts of a coupling agent and 64-169 parts of polyisocyanate. The all-water foaming cold-cure foam fireproof sealant has the beneficial effects that the substrate attaching force is more excellent, the light weight can be guaranteed, and the requirements on environment protection can also be met; a quaternary ammonium salt temperature-sensitive catalyst is used as an anti-hydrolysis gel catalyst and meets the field utilization requirements without heating conditions; and a formed foaming layer not only has excellent fire resistance, but also can be expanded to form a firm and dense carbon layer after a fire disaster occurs, so as to prevent flame from spreading and prevent heat propagation.

The invention discloses a diffuser and flame tube optimal matching experimental research device which comprises an electric driving device, and further comprises an air inlet channel, an air compressor, a diffuser, a combustion chamber and an air outlet which are connected in sequence, and the diffuser and flame tube optimal matching experimental research device is used for simulating the sectionsof the air inlet channel, the air compressor and the combustion chamber of a typical gas turbine engine. The diffuser and flame tube optimal matching experimental research device can flexibly replacedifferent impellers and diffusers to set different inlet parameters for experimental simulation, so that the research of optimal matching between the low-loss diffuser and the flame tube becomes practical. Through the adoption of the diffuser and flame tube optimal matching experimental research device, the relation between an actual upstream inflow condition of the flame tube and the performanceof the flame tube can be researched, the influence rule of diffuser design on the flow field organization, flow distribution and combustion performance of the flame tube and a head is mastered, a low-loss diffuser optimization method and an optimal matching method with the flame tube and the head are formed, and therefore the diffuser and flame tube optimal matching experimental research device is of important significance in realizing advanced combustion organization of the flame tube.

The invention discloses a preparation method of a novel polyester fiber and particularly relates to the preparation method of a high-comfort triangular hollow microporous fiber which is newly developed and has the advantages of being dry, comfortable, cool and refreshing, capable of absorbing sweat and draining moisture, light, good in warm keeping, easy to clean, fast to dry and the like. According to the preparation method of the high-comfort triangular hollow microporous fiber, the online measurement addition technique and a melt spinning process are adopted, three symmetrical V-shaped spinneret plates serve as spinneret assemblies to obtain the fiber, and an alkali reduction process is performed to obtain the high-comfort triangular hollow microporous fiber. The fiber fabric has the advantages of being dry, comfortable, cool and refreshing, capable of absorbing sweat and draining moisture, easy to clean, fast to dry, light, good in warm keeping and the like.

The invention discloses an automobile body framework which comprises a front compartment framework, a battery pack compartment framework, a tail compartment framework and top cover beams. The rear end of the front compartment framework is fixedly connected with the front end of the battery pack compartment framework. The rear end of the battery pack compartment framework is fixedly connected with the front end of the tail compartment framework. The front end of each top cover beam is fixedly connected with the front compartment framework and the rear end of each top cover beam is fixedly connected with the tail compartment framework. A battery pack compartment front cross beam and a battery pack compartment rear cross beam are arranged in the middle rear portion of the battery pack compartment framework. Each of the two sides of the battery pack compartment framework is provided with an outer longitudinal beam and an inner longitudinal beam. The two ends of each outer longitudinal beam and the two ends of each inner longitudinal beam are fixedly connected with the battery pack compartment front cross beam and the battery pack compartment rear cross beam. Each inner longitudinal beam is located on the inner side of the corresponding outer longitudinal beam. One end of each inner longitudinal beam inclines towards one end of the corresponding outer longitudinal beam. An acute angle is formed between each inner longitudinal beam and the corresponding outer longitudinal beam. A fixing frame is formed by the inner longitudinal beams on the two sides, the battery pack compartment front cross beam and the battery pack compartment rear cross beam. The mass of a whole automobile is small, the arrangement optimization of a battery pack is guaranteed, and danger caused by collisions is avoided.

The invention provides a lightweight design method under the infinite life of the structure. In the design process, the static strength and fatigue strength of the dangerous position of the structureare higher than the value of the structural stress, which is just the ideal design margin, so as to ensure the lightweight of the structure. The stress in the dangerous position of the structure is less than the fatigue limit, which ensures the infinite life of the structure. Through the stress field and static strength field and the lightweight matching design between stress field and fatigue strength field, based on the quantitative matching of static strength field and fatigue strength field, the design and the manufacture are coupled to realize the lightweight design under the infinite life of the structure, which ensures the maximum utilization of structural materials and strength potential under the infinite life of structure.

The invention discloses a lignin enhanced polyvinyl chloride wood plastic foam composite material, and a preparation method thereof. The lignin enhanced polyvinyl chloride wood plastic foam compositematerial is composed of, by weight, 100 parts of polyvinyl chloride, 10 to 200 parts of wood fiber powder, 2 to 200 parts of an inorganic powder, 1 to 20 parts of a stabilizing agent, 1 to 10 parts ofa lubricant, 5 to 80 parts of lignin, 1 to 8 parts of a compatilizer, 1 to 10 parts of a foaming agent, 8 to 25 parts of a foaming conditioning agent, and 0.5 to 10 parts of a reinforcing agent. Compared with the prior art, the preparation method comprises following advantages: lignin enhancing technology is combined with micropore foaming technology, so that material lightweighting is ensured, and the plasticizing performance, the flame resistance, the ultraviolet resistance, the aging resistance, the biological resistance, the radiation resistance, and rheological performance, the screw extrusion performance, and the heat resistance of the lignin enhanced polyvinyl chloride wood plastic foam composite material are improved obviously, product surface gloss is improved, product water absorption performance is reduced, and the high performance lignin enhanced polyvinyl chloride wood plastic foam composite material with lightweighting characteristics is obtained.

The invention belongs to the technical field of identity card identification, particularly relates to a mobile terminal identity card image occlusion judgment method. According to the invention, a light-weight identity card detection network is used for positioning an identity card area. The method comprises the following steps: preparing identity card shooting pictures of various scenes, markingthe position of an identity card by using a horizontal rectangular frame to form a training sample, adding a part of pictures without the identity card into the training sample to serve as negative samples, and outputting coordinate information of an identity card external rectangular frame in the input pictures after network training; and judging whether the identity card is shielded or not by using a lightweight classification network, and properly expanding the external rectangular area of the identity card obtained in the first step, cutting and sending the external rectangular area into the network for classification, and finally obtaining a result whether the identity card is shielded or not. According to the method, the occlusion judgment of the identity card image is completed by using the two lightweight network models, and the method has the characteristics of exquisite model, high speed, high accuracy and high robustness.

The invention relates to a capacity allocation method applied to a rail transit vehicle-borne hybrid energy storage system. The method comprises a step of defining a weight weight factor (alpha) and a charging energy weight factor (Q), a step of substituting the traction condition information of a train, alpha, Q and energy storage component parameters of the vehicle-borne hybrid energy storage system as input into each boundary condition of an energy demand, a charging power demand and a discharge power demand of the vehicle-borne hybrid energy storage system, outputting a boundary value of a total weight of the vehicle-borne hybrid energy storage system separately, and recording a maximum value in three boundary values as the total weight of the vehicle-borne hybrid energy storage system needing to be configured actually in this time of alpha and Q allocation, and a step of obtaining an optimal capacity allocation scheme through the optimized calculation and adjustment of alpha and Q. Accoding to the method, while the train traction is satisfied, with the weight of the vehicle-borne hybrid energy storage system as an optimization target, an optimized capacity allocation scheme with the coupling of different types of energy storage components are made through optimized calculation, and a new way of thinking is provided for the capacity allocation of the vehicle-borne hybrid energy storage system.

The invention discloses a preparation method of shading screen cloth with antibacterial and antiageing performances. The prepared shading screen cloth is of a double-layered composite structure. The preparation method comprises the following steps: firstly, separately synthesizing outer screen cloth of an anti-ultraviolet layer and inner screen cloth of an antibacterial layer; then preheating and melting the two screen cloth through adjustment variation of the temperature of a heating roller, and assisted by an adhesive, pressing a rubber roller with an iron roller, and forming cooling forming to boating the shading screen cloth. The shading screen cloth of the double-layered composite structure is directly prepared from functional composite high molecular fibers separately without adding an anti-ultraviolet agent and an antibacterial agent. A finished product not only has an excellent anti-ultraviolet function, but also has a strong antibacterial and anti-mold property, is stable in chemical property, and also avoids use of external additives. Various stretch resisting, anti-ageing, corrosion-resisting, radiation-resisting and light characteristics of the screen cloth are guaranteed to the maximum.

The invention relates to a double-cylinder by-pass type magnetorheological vibration damper. The vibration damper comprises a working cylinder barrel, a liquid storage cylinder barrel, a piston and apiston rod, wherein the piston rod penetrates through a guide ring, and the guide ring is connected with a liquid storage cylinder body together; a magnetorheological effect valve and the whole vibration damper are installed together by the guide ring; a magnetic conductive sleeve connected with the magnetorheological effect valve by a magnetic insulation gasket is sequentially provided with an upper magnetic conductive plate, a magnetic insulation washer, a middle magnetic conductive plate, a magnetic insulation washer and a lower magnetic conductive plate along the inner axial direction; electromagnetic coils are sleeved on the circumferences of the upper magnetic conductive plate, the middle magnetic conductive plate and the lower magnetic conductive plate by magnetic insulation sleeves; the middle parts of the upper magnetic conductive plate and the lower magnetic conductive plate are provided with axial through holes communicated with a liquid discharge hole and a press plate oilduct; and three arc grooves are uniformly distributed at the circumference of the middle magnetic conductive plate. When the piston rod moves, magnetorheological fluid flows among a working cylinder,the magnetorheological effect valve and a liquid storage cylinder. The invention can ensure a larger stroke and be beneficial to dissipating the heat of the electromagnetic coils; and the flow of themagnetorheological fluid in the coils not only can generate large damping force but also ensure portable integration.

The object of the present invention is to provide a fuel tank structure which can protect a fuel pump unit while suppressing the increase of the weight of the fuel tank and maintaining the appearance of the fuel tank. A center portion opening (122) formed in a fuel tank is closed by a lid portion (123) of a setting plate (121), an opening which allows a discharge pipe (124) extending from a fuel pump unit to pass therethrough is provided in the lid portion (123), and an upper portion of the fuel pump unit (120) is covered with the setting plate (121). Here, a gap (126) is ensured below the lid portion (123) to ensure the fastening ability of bolts (125a) and nuts (125b).

The invention discloses a lightweight RFID rapid authentication method. The method comprises the following steps: S101, a reader generating a random number R and sending a request message R to a tag;S102, after the tag receives the request message of the reader, calculating M=H(key) and (img file), and sending the left half part NL and the left half part M of N to the reader; S103, after the reader receives the message <M,NL>, judging whether M is equal to M (shown in the description) or not; S104, the label receives the NR; judging whether the calculated NR is equal to the NR (Noise Ratio) or not according to the formula shown in the specification, and judging whether the calculated NR is equal to the NR or not according to the formula shown in the specification; and if the number of thetag authentication readers is equal to the number of the updated secret keys, the tag authentication readers are legal, and if the number of the updated secret keys is not equal to the number of theupdated secret keys, the protocol is terminated. According to the invention, secure bidirectional authentication can be ensured, and the lightness of the protocol can be ensured; and only one Hash operation is carried out at the tag end, so that the limitation of the RFID tag hardware resources is met.

The invention relates to a space bifacial phase angle laser detecting system, which comprises a detection assembly platform, a push-pull mechanism marker post device, an orienting button marker post device, a push-pull mechanism demarcating plate device, an orienting button demarcating plate device, a first CCD image acquisition device, a second CCD image acquisition device, a first acquisition card, a second acquisition card, a laser and an adjusting bracket thereof, and a computer provided with measurement software. The system has the advantages that: (1) the system can quickly and accurately finish the measurement of a 85-degree space bifacial phase angle of a rocket shell; and (2) the measurement result is nearly not influenced by the rigidity of the detection assembly platform of the rocket shell and other factors, the requirement for the integral rigidity of the detection assembly platform can be greatly reduced, and the light weight of the detection assembly platform is ensured.

A recorded data eraser 1 defines therein a cavity 2 for insertion of a hard disk drive 20 in the cavity 2 and includes a coil 4 being arranged around the cavity 2 so as to encircle the hard disk drive 20 when the hard disk drive 20 is inserted in the cavity 2, and a DC power supply circuit 8 for producing a magnetic field in the coil 4.

The invention provides a vehicle key generating and issuing method and device which are applied to a key generator, a key issuing terminal and a vehicle key management terminal, and the method appliedto the key generator comprises the steps of receiving key generating parameters; reading a key generation root; according to the key generation parameter and the key generation root, generating a keyaccording to a target algorithm; generating key issuing information according to the key, wherein the key issuing information comprises a key verification code; and sending the key issuing information to a key issuing terminal. By implementing the method and the device, the security of storing the key generation root can be improved, so that the security of key generation is ensured, a huge database is not required to store and back up the key, the lightness of a key generation system is ensured, and the deployment is convenient.

Provided is a steel bridge deck pavement structure with reinforced construction. The steel bridge deck pavement structure is jointly composed of a prefabricated reinforced steel plate (1), an anticorrosion layer (2), a waterproof layer (3), a lower surface layer (4), a fiber grid (5) and an upper surface layer (6) from bottom to top, and is characterized in that the top surface of the prefabricated reinforced steel plate (1) is provided with the reinforced construction, the fiber grid (5) is composed of longitudinal grid ribs (51) and transverse grid ribs (52) in a mutual interlaced mode, theinteriors of the lower surface layer (4) and the upper surface layer (6) are mixed with reinforced short fibers, and the fiber grid (5) is poured between the lower surface layer (4) and the upper surface layer (6) or into the upper surface layer (6), and achieves common working with the lower surface layer (4) and the upper surface layer (6) through surface construction. The steel bridge deck pavement structure with the reinforced construction has a good interlayer bonding performance, and can effectively prevent the risk of interlayer cracking and pavement layer fatigue cracking, meanwhile, through a novel prefabricated reinforced steel plate mode, the construction technology is simplified, the construction efficiency is greatly improved, the production installment cost is saved, the building cost of projects is reduced, and the normal use and durability needs of a bridge structure can be met.

The invention relates to a method for preparing honeycomb enhanced phenolic foam composite materials. The method is characterized by including the steps of: (1) pouring phenolic resin foam composite into a die; (2) vertically placing a honeycomb in the phenolic resin foam composite in the die; (3) placing the die with the phenolic resin foam composite and the honeycomb in the step (2) into a baking oven at the temperature of 50-100 DEG C for foaming for 5-10h, and obtaining the honeycomb enhanced phenolic foam composite material. Via one-time soaking and heating consolidation, the method is capable of preparing the honeycomb enhanced foam composite materials with phenolic foam ingredients in the honeycomb materials and phenolic foam filled in honeycomb lattice holes, the operation procedure is extremely simple, only the die and the baking oven are utilized as equipment, so that the method has the advantages of efficiency and low cost, meanwhile, the composite material products can be guaranteed to have the advantages of good combination properties like light weight, sound insulation, heat insulation, specific strength, specific modulus, water resistance and flame retardance.

The invention relates to the field of vehicle engineering, and discloses a suspension valve group, a hydro-pneumatic suspension control system, a hydro-pneumatic suspension control method, and a vehicle. The hydro-pneumatic suspension control system comprises suspension cylinders (2) which are symmetrically arranged, a left accumulator (31) and a right accumulator (32), and an oil feeding pipe (4) and an oil returning pipe (5). The oil cavities of the left accumulator (31) and the right accumulator (32) are respectively communicated with the rod chambers of the suspension cylinders at the opposite sides, and can be selectively communicated with the rodless chambers of the suspension cylinders (21) at the same sides so as to selectively switch a hydro-pneumatic suspension to a rigid or flexible state. The rodless chambers of the suspension cylinders (2) can be selectively communicated with the oil feeding pipe (4) or the oil returning pipe (5). When the hydro-pneumatic suspension is selectively switched to the rigid state, the rod chamber of at least one suspension cylinder (2) can be selectively communicated with the oil returning pipe (5). By adopting the hydro-pneumatic suspension control system and the hydro-pneumatic suspension control method of the invention, lifting operation can be implemented in the rigid state.

The invention discloses a special pipe press for stage pipe fittings. The pipe press comprises a base, a pipe head loading vibration disc and a pipe body loading manipulator; the base is provided witha pipe receiving turntable and a main motor; multiple pipe receiving clamping grooves are formed in the pipe receiving turntable; multiple movable pressing heads are arranged on the pipe receiving turntable; an end surface cam is arranged on the base; the base is provided with a receiving base; the movable pressing heads are slidingly connected with the pipe receiving turntable; the pipe receiving turntable is provided with multiple return springs for driving the movable pressing heads to return; the return springs correspond to the movable pressing heads one to one; and the base is providedwith a limiting body for limiting axial movement of pipe bodies. The pipe press has the beneficial effects of capability of automatically loading, pressing and assembling the pipe bodies and pipe heads, high stability in the positioning and assembly process, high production efficiency and good assembly effect.

The invention discloses a method for preparing an electromagnetic shielding foamed aluminum composite material. The method includes the steps that a magnesium block and a hollow ceramics microsphere are added by stepping composition, then, after a pre-treated titanium hydride foaming agent is added, the surface is provided with a layer of dense oxidation film, thus the mixture can be foamed intensively in a certain temperature range, the effect of aperture decreasing is realized, and finally, a novel closed-cell foamed aluminum composite material is obtained. According to the method for preparing the electromagnetic shielding foamed aluminum composite material, the obtained closed-cell foamed aluminum composite material has the characteristics of being low in cost, small in aperture, highin strength, excellent in electromagnetic shielding performance and the like.

The invention discloses a lightweight aggregate. Steel mill sludge is used as a raw material to prepare the aggregate, the raw material formula of the aggregate comprises 10-40% of the steel mill sludge and 60-90% of fly ash. A specific preparation method of the aggregate comprises the following steps: the steel mill sludge is dried, crushed and ground, and sieved, the sieved fly ash is added according to a certain weight ratio, the sludge and the fly ash are uniformly mixed, the obtained mixture is pelletized, and obtained raw material pellets are dried for a certain time, then undergo heat treatment, and finally are sintered and cooled to obtain the finished aggregate. The lightweight aggregate obtained in the invention has the characteristics of high strength, low density, good heat insulation performance and low water absorption rate; and the sludge and fly ash are only used to obtain the lightweight aggregate with a certain heat insulation property, and the raw materials are solidwastes, so the preparation method has the advantages of realization of changing wastes into valuables, energy saving, environmental protection, and reduction the aggregate preparation cost.

The invention discloses a novel historical relic protection box. The protection box comprises a box body which is divided into an upper box body and a lower box body and further comprises locking bolts and clamping devices; the locking bolts fix the multiple clamping devices into the box body, trapezoid protrusions are arranged on the boundary of the upper box body, trapezoid grooves are formed in the boundary of the lower box body, the trapezoid protrusions are embedded in the trapezoid grooves to enable the upper box body and the lower box body to be buckled, and then the upper box body and the lower box body are fixed through clamping buckles and clamping buckle seats; each clamping device comprises a bearing table, a limiting device, a buffer pad and a clamping plate, wherein a limiting device hole groove is formed in the bearing table, historical relics are flatly laid on the upper surface of the bearing table, the limiting device penetrates the limiting device hole groove to fix the historical relics, the buffer pad is flatly laid on the upper surface of the historical relics, the clamping plate is flatly laid on the upper surface of the buffer pad, and the bearing table and the clamping plate are fixed through the locking bolts; and the protection box has the beneficial effects of being light, high in strength, free of dampness and bonding, simple in structure, convenient to use, long in hold time and not prone to damping the historical relics.

A recorded data eraser 1 defines therein a cavity 2 for insertion of a hard disk drive 20 in the cavity 2 and includes a coil 4 being arranged around the cavity 2 so as to encircle the hard disk drive 20 when the hard disk drive 20 is inserted in the cavity 2, and a DC power supply circuit 8 for producing a magnetic field in the coil 4.

The invention discloses a heat-resistant impact-resistant polypropylene composition and a preparation method thereof, and belongs to the technical field of polypropylene materials. The polypropylene composite is characterized by comprising the following components in parts by weight: 100 parts of a polypropylene resin powder, 0.03-0.3 part of a hyper-branched polymer powder, 0.02-0.1 part of an inorganic nucleating agent, 0.05-0.3 part of an antioxidant, 0.02-0.1 part of an acid absorbent, and 0.03-1.0 part of an antistatic agent, wherein the polypropylene resin is a homo-polymerized polypropylene resin powder, a melt mass flow rate of the homo-polymerized polypropylene resin under the conditions of 2.16 kg and 230 DEG C is 20-60 g / 10 min, the isotacticity of polypropylene is 95% or more,and Mw / Mn is 4-12. Through the synergistic effect of a small amount of hyper-branched polyethylene and a small amount of nano-scale white carbon black added in the composition, the rigidity and toughness balance of a product is achieved, the crystallization speed is increased, and the crystallization behavior of polypropylene is improved, so that the size of resin crystals is finer and denser, thescattering and refraction of an incident light are reduced, and the glossiness of the product is increased.