478results about How to "Not easy to pull out" patented technology

The invention discloses an underground drilling and fracturing-integrated staged fracturing device. The device comprises a drill, a first packer, a first staged drill stem, an interception water distribution rod, a second packer, a second staged drill stem and a function conversion rod which are communicated from front to back sequentially, a first ball, a second ball, and a third ball; an underground drilling and fracturing-integrated staged fracturing gas drainage process is implemented on the basis of the technology of the underground drilling and fracturing-integrated staged fracturing device. Through the underground drilling and fracturing-integrated staged fracturing device and the underground drilling and fracturing-integrated staged fracturing gas drainage process, the integrationof drilling and fracturing is realized, the drill hole wall in a wider range can be opened and is extended and cracked, and fracturing can be can be performed more pertinently; and compared with a non- staged fracturing method, the process has the advantage that the air permeability coefficient of a coal bed is improved greatly.

The invention discloses a packaging method of a soft-package lithium ion battery, comprising the following steps: fixing a battery to be packaged; piercing an air bag of the battery to be packaged, and vacuumizing the air bag; and packaging the battery to be packaged, wherein, a joint part between the air bag of the battery to be packaged and a main body of the battery is always higher than the main body of the battery. By adopting the packaging method of soft-package lithium ion battery for packaging the battery, the joint part between the air bag of the battery to be packaged and the main body of the battery is always higher than the main body of the battery, so electrolyte returns to the main body of the battery and is not easily extracted in vacuum, thus effectively avoiding an external packaging material of the battery from being polluted and corroded by the electrolyte, and obviously improving consistency of battery performance.

The invention relates to a crude polypropylene fiber and a preparation method thereof. The crude polypropylene fiber provided by the invention is a mixture consisting of 85-99% (weight percent) of polypropylene, 0.1-10% of inorganic packing, 0.5-5% of a compatibilizer, 0.1-0.5% of antioxidant and 0.1-0.3% of ultraviolet absorber, and the surface of the crude polypropylene fiber is in the shape of waves or bamboo joints. The preparation method comprises the following steps of: firstly, drying the inorganic packing until the inorganic packing is constant in weight; then, mixing the inorganic packing with the other materials in certain proportion to obtain a mixed material; extruding the mixed material by a twin-screw extruder, and spinning by a spinneret plate; sequentially carrying out water cooling, hot-water drafting, hot-roller drafting and thermoforming on the obtained product to obtain a crude fiber; and finally, carrying out surface creasing treatment on the crude fiber. In the method disclosed by the invention, the polypropylene is modified by using the low-price inorganic packing to obtain a high-strength and high-modulus polypropylene crude fiber, thereby enhancing the strength of concrete and prolonging the service life of the concrete. In the invention, modification and spinning processes are completed in a step, thereby facilitating simplification of a production process and reduction of the product cost.

The invention discloses a nanometer filler cooperatively filling epoxy resin composite coating. The composite coating is prepared from the following components in percentage by weight: 60-70 percent of epoxy resin, 26-34 percent of polyamide resin, 1-3 percent of modified nanometer Al2O3 and 1-3 percent of modified nanometer SiO2, wherein sum of the mass percent of the components is 100 percent. A preparation method comprises the following steps: respectively preparing the modified nanometer SiO2 and the modified nanometer Al2O3, respectively preparing the epoxy resin and the polyamide resin into solutions, adding the modified nanometer Al2O3 and the modified nanometer SiO2 in the epoxy resin solution, stirring, then adding the polyamide resin solution, soaking treated carbon fiber fabrics, and curing to obtain the composite coating. The nanometer filler cooperatively filling epoxy resin composite coating is applied to the surface of a steel block. With the adoption of the preparation method, the problem of poor abrasion resistance of a single nano particle filling epoxy resin composite coating is solved, and the prepared composite coating has good impact and abrasion resistances.

The invention relates to the technical field of automobile parts, in particular to a window glass unit mounted on an automobile, and specifically provides the window glass unit which comprises an injection molding covering edge and a bright decorative strip. The window glass unit comprises a glass plate, an edge covering structure and the bright decorative strip, wherein the edge covering structure is provided with a first bulge and a second bulge; a plurality of locking through holes are formed in the bottom surface of the edge covering structure between the first bulge and the second bulge; a plurality of locking clips are integrally arranged at the lower parts of a first long edge and / or a second long edge of the bright decorative strip in a manner of downward extending; the locking clips correspond to the locking through holes one by one and can be clamped into the locking through holes. According to the window glass unit, a clamping force, a pulling-out force and a clamping-in force can be flexibly changed, so that the assembling and installing process is simple, the window glass unit is not easy to pull out, the assembling effect is firm and the like, and the locking clips are not damaged after a plurality of times of installation and detachment; other installation accessories, such as clips, 3M adhesive tapes and the like, are not needed, so that the assembling materials are saved and the cost can be more optimized.

Provided are an abrasion-resisting epoxy resin / carbon fiber composite coating and a preparation and coating method thereof. The composite coating is formed by curing a carbon fiber fabric arranged in a matrix solution, wherein the matrix solution consists of 64-66.5 parts by weight of epoxy resin, 32-33.5 parts by weight of polyamide resin, a butanone solution, a methylbenzene solution and 1.5-2.5 parts by weight of nano inorganic filler modified by a silane coupling agent, the proportion of the volume of the butanone solution to the total weight of the epoxy resin is 2.4 mL:1g, and the proportion of the volume of the methylbenzene solution to the total weight of the polyamide resin is 2.4 mL:1g. The composite coating is applied to a cushioning material formed on the steel block surface. The carbon fiber fabric, spherical nano TiO2, layered nano-montmorillonite and epoxy resin matrix form a firm net crosslinking structure, the interface bonding force is strengthened, and carbon fiber is not easily pulled out from the composite coating in the friction process. The surface roughness of the composite coating is further reduced, and the abrasion-resisting performance of the composite coating is improved.

The invention discloses a RFID mark special for a cuttlefish, which comprises a main body, wherein one end of the main body is provided with a conical head; the side wall of the head is provided with threads; the side wall of the other end of the main body is provided with a tail which is radial along the side wall of the main body; and a hollow cavity is arranged in the main body. The invention has the advantages that the mark is difficult to drop off after being fixed, the technique is simple and the structure is novel. The mark is fit for being used as a releasing mark for sepiella maindroni de rochebrune multiplication in order to evaluate the multiplication effect.

The invention provides a fuse mounting structure. The fuse mounting structure comprises an electric appliance box main body and a fuse holder, wherein slots are formed in the two sides of the electric appliance box main body; first bosses and second bosses are arranged inside the slots; the fuse holder comprises a fuse mounting part, clamping parts positioned on the two sides of the fuse mounting part, and two insertion parts positioned below the fuse mounting part; the insertion parts comprise sliding chutes with sealed upper ends and lower ends, and bulges protruded in the directions far away from the sliding chutes; the insertion parts of the fuse holder are inserted in the slots of the electric appliance box main body; the second bosses are positioned in the sliding chute; under the working condition, the first bosses are buckled with the bulges, and meanwhile the second bulges are not in contact with the lower ends of the sliding chutes; under the out-of-service condition, the first bosses squeeze the bulges to enable the insertion parts to be deformed towards the sliding chutes, and meanwhile the second bosses are in contact with the lower ends of the sliding chutes. The fuse mounting structure disclosed by the invention is convenient to operate and high in safety.

The invention discloses a method and device for supporting a weak adhesion bond soft rock roadway. The method includes that step 1, a drilling machine is adopted for drilling holes; step 2, a reamer bit and a drilling stem are connected, and the bottom of a drilled hole is chambered; step 3, an anchoring agent and an anchor rod are placed in the drilled hole, the anchor rod and the drilling machine are connected, the drilling machine drives the anchor rod to rotate and stir the anchoring agent, after the anchoring agent is solidified, a chambering portion is full with the anchoring agent to form a solid structure in a reverse wedge shape, and the solid structure is used for fixing an anchoring section of the anchor rod; and step 4, a tray is arranged on top of the drilled hole, a nut is used for screwing a free end of the anchor rod tightly, and pre-tightening torsion meets design value. The device is a chambering reamer bit comprising a casing, a cutter and a cutter control device, wherein one end of the casing is a connector, the cutter is connected with the bottom of the connector in pivoted mode, and the cutter control device is connected with the cutter and controls the cutter to be screwed out from the casing or withdrawn. By means of the device and method, an effect of the anchor rod is good.

The invention relates to high-strength wear-resistant flame-retardant polypropylene and a preparation method thereof. The polypropylene is prepared from the following components in parts by weight: 42-55 parts of a polypropylene base body, 20-29 parts of modified packing, 1-4 parts of boron nitride, 18-21 parts of additives, 1-3 parts of a phosphite antioxidant and 2-5 parts of dimethicone. The preparation method comprises the following steps: uniformly mixing the polypropylene base body, the modified packing, the boron nitride, the additive, the phosphite antioxidant and the dimethicone by virtue of a high speed mixer; adding the mixed material into a granulator to be granulated; and then adding aggregates into an injection moulding machine to prepare a sample so as to prepare the flame-retardant polypropylene. According to the flame-retardant polypropylene provided by the invention, various inorganic components are added to improve the flowability of a polymer and an inorganic packing system and enhance the toughening effect, and no bulking agents are used, so that the cost is lowered. The additives, glass fibers and a flame retardant are halogen-free materials, the preparation process is simple and convenient, the adopted materials are cheap, and the comprehensive cost is relatively remarkable in advantage compared with that of a conventional polypropylene composite material.

The invention relates to an anti-thermal shock iolite fireproof kiln furniture and a preparation method thereof. The fireproof kiln furniture comprises the raw materials of 25-37% of a matrix, 50-56% of an aggregate, 4-5% of a sintering agent and 9-14% of a fiber reinforced material, wherein the matrix is composed for 15-25% of kyanite fine powder, 15-25% of kaolin fine powder, 48-69% of and alusite fine powder, and 1-2% of magnesia fine powder, and the aggregate is composed for 60-75% of gangue and 25-40% of high bauxitic clay clinker. In the prepared fireproof material, acicular iolite and cylindrical mullite are interlaced to a net state, the particles are in a free state with uniform size, the matrix and the particles have a certain buffer area, a certain stress is absorbed, and crack dynamic expansion is avoided. An iolite-mullite multiphase is generated in the fireproof product, synchronous increase of flexural intensity and compression strength can be satisfied, and the heat stability of the final product is increased.

A novel dual-axial filling knitted fabric, which is the combination of woven fabric and knitted fabric, is composed of basic stitch (weft flat stitch), warp and weft on the back of basic stitch. Saidwarp interwoven with weft is alternatively presented on front and back surfaces of weft flat loop arc at intervals of two loop columns. A special warp-weft feeder of flat knitting machine is used. Its advantages are not layer separation of warp and weft, and better drapability.

The invention discloses a method for fixedly installing and leveling a base of a metal upright column of a bridge guardrail. The method includes leveling the base by the aid of a leveling device and fixedly welding the leveling device on a reinforcement cage by short reinforcing steel bars; removing the base construction leveling device and mounting corresponding base fixing devices on a bottom plate; and installing the metal beam-column guardrail after concrete is molded by means of pouring. The method has the advantages that a construction procedure is simple and is easy to learn, the leveling precision is high, the requirement on anchoring strength is met, the base leveling device can be reused, the construction speed is increased, the construction quality is improved, and the construction cost is reduced.

The invention provides a connector which can be miniaturized easily while exhibiting high mounting density and high contact reliability. The connector comprises a base (11) having in the front an opening (11a) for receiving the tip portion (51) of an FPC (50) and first and second insertion holes (13, 14) juxtaposed alternately in the front and the rear, a first connection terminal (20) inserted into the first insertion hole (13) and having a first movable contact (23) which can come into pressure contact with the first joint (52) of the FPC (50), a second connection terminal (30) inserted into the second insertion hole (14) and having a second movable contact (33) which can come into pressure contact with the second joint (53) of the FPC (50), and an operating lever (40) supported rotatably by the base (11) and having first and second operating portions (42, 43) capable of operating the first and second connection terminals (20, 30) and juxtaposed alternately at the edge on one side.

Provided is a printing device for which configuration is simplified and with which the ink ribbon can be appropriately fed in both directions between a supply roll and a take-up roll on which the ink ribbon is wound. The printing device (1) is provided with: a supply roll (4), a take-up roll (5), and a power transmission mechanism (31) for transmitting motive power from a drive source (30) to the supply roll (4) and the take-up roll (5). If the direction in which the take-up roll (5) winds the ink ribbon (3) is called the ribbon winding direction and the direction in which the supply roll (4) winds the ink ribbon (3) is called the ribbon rewinding direction, the power transmission mechanism (31) is provided with: a one-way clutch for transmitting the driving force of the drive source (30) to the take-up roll (5) in the ribbon winding direction and blocking the transmission of the driving force of the drive source (30) to the take-up roll (5) in the ribbon rewinding direction; and a one-way clutch for transmitting the driving force of the drive source (30) to the supply roll (4) in the ribbon rewinding direction and blocking the transmission of the driving force of the drive source (30) to the supply roll (4) in the ribbon winding direction.

The invention provides a closed type pipe clamp assembly with a vibration-proof structure. The closed type pipe clamp assembly consists of a pipe clamp body and vibration-proof pads, wherein the pipe clamp body consists of a pipe clamp seat and a pipe clamp cover; one half-hole slot and a bolt mounting hole are arranged on the pipe clamp seat, and correspondingly, the other half-hole slot is arranged on the pipe clamp cover; the pipe clamp cover is covered and connected to the pipe clamp seat; the two half-hole slots together enclose to form a pipe fixing hole; the vibration-proof pads are of two half ring structures and respectively clamped in the two half-hole slots; and the size of a hole enclosed by the two half ring vibration-proof pads is matched with the diameter of a pipe required to be clamped and fixed. The closed type pipe clamp assembly can reduce vibration transmitted to a vehicle body by the pipe, and the pipe clamp vibration proof effect can be adjusted. The closed type pipe clamp assembly is portable to assemble, not easy to fall off and accurate to position. The pipe is fixed in a totally-enclosed mode, thus the requirement on the assembling of pipes with different diameters, and the like can be met without newly developing the whole pipe clamp.

The invention discloses a built-in double pin locking device of a sliding rail of an automobile seat, comprising a lock (1), a key (2), a fixed rail (01), a sliding rail (02) and a side plate (03). The built-in double pin locking device of the sliding rail of the automobile seat adopts the following technical proposal: the sliding rail is provided with the lock and the key; the lock is internally provided with two pins driven by a sliding core which is controlled by the key to move up and down; the bottom of a fixed rail groove is provided with a plurality of locking holes with the distance being 2 / 3 of the distance of the two pins; when in locking, the key is tripped every time, only one of the two pins is inserted into the locking holes of the bottom of the fixed rail groove so as to lock the sliding rail, therefore, the defects that the prior art has complex structure, easiness of control failure and unlocking, and no fine tuning function; and the provided built-in double pin locking device of the sliding rail of the automobile seat uses the characteristics of fine tuning function of the double pins and strong tear resistance of the round locking holes to achieve the purposes of fine tuning function, simple and firm structure, shock resistance, and control-failing and unlocking resistance.

The invention discloses a production method of a hot-rolling seamless steel pipe billet. The production method is characterized by comprising the following steps of (1) steel making, (2) continuous casting and (3) pipe rolling and online heat treatment. The method is simple in step and convenient to operate, in the steel making procedure, specially-designed low-alkalinity acid synthesis refining slag is adopted to perform refining, brittle slag inclusion in steel is converted into plastic slag inclusion, and therefore in the cold drawing process of the hot-rolling seamless steel pipe billet for an oil cylinder, the pipe billet is not prone to being drawn to be cracked, and white spots, pits and other defects which affect the product quality and are caused by the brittle slag inclusion do not easily appear in the surface of a machined steel pipe. Therefore, the quality of the manufactured seamless steel pipe billet can be improved, and the pipe billet can be suitable for being used and popularized.

The invention discloses a bracing type single-edge bolt fastener, which is characterized by comprising a screw stem with an axial center through hole, wherein the tail section of the screw stem is a threaded rod which is matched with a screw cap, the middle section of the screw stem is a smooth rod, and the front section of the screw stem is a support head; the support head is provided with a hollow inner cavity, an opening is formed in a symmetrical cross position on the side wall of the support head to form four elastic segments which can be braced in an umbrella shape, the inner side walls of the elastic segments are inclined faces, and the front diameter of the hollow inner cavity is enabled to be larger than the tail diameter of the hollow inner cavity due to each inclined face; a pulling rod is arranged in the center axial through hole of the screw stem in a penetration way, and a cross brace rod is fixedly connected onto the front end of the pulling rod in a T shape; and by the adoption of the pulling rod, the cross brace rod can be driven to move forward to the tail section side of the screw stem, and the four elastic segments are braced in the umbrella shape through the cross brace rod. According to the bracing type single-edge bolt fastener, only a bolt is needed to be mounted on one side, and the single-edge operation of the bolt is realized.

The invention discloses a vegetation ecological concrete slope protection structure and a construction method, which comprises a soil slope, one side of the soil slope is provided with a solid cage toe wall, and a slope protection net box is arranged above the soil slope, and the slope protection net box is filled with For ecological concrete, the side of the slope protection net box away from the soil slope is provided with a first installation groove, and a fixed pile is arranged in the first installation groove, and one end of the fixed pile penetrates the inner bottom of the first installation groove and extends into the soil slope. The invention has a simple structure, and the ability of the surface of the soil slope to resist the impact of rainwater is enhanced by cultivating root plants with ecological concrete in the slope protection net box. The card slot is separated, the rotating sleeve is rotated, and the first card block is connected with the first card slot to drive the rotating shaft to rotate, and the connecting rod drives the insert plate to insert the insert plate into the soil slope, so that the fixed pile is not easy to pull out, thereby strengthening the slope protection The connection strength between the cage and the soil slope.

The invention relates to a three-dimensional suction arm movement mechanism of a cellular dust collector. The mechanism comprises a transverse rail (1), a longitudinal rail (2), a cart (3), a trolley (4) and a transmission suction box (5), wherein the cart (3) is arranged on the transverse rail (1); the longitudinal rail (2) is arranged at the bottom of the cart (3); the trolley (4) is arranged on the longitudinal rail (2); the transmission suction box (5) is arranged at the bottom of the trolley (4); the transmission suction box (5) comprises a transmission box (6) and a header box (7); the transmission box (6) is provided with a plurality of rotary suction ports (8); and one end of each rotary suction port (8) is bent, and the other end of each rotary suction port (8) stretches into theheader box (7) and is communicated with the header box (7). The three-dimensional suction arm movement mechanism of the cellular dust collector is compact in structure, runs normally under the severeworking condition of high dust quantity in a closed space, and is difficult to slip and low in fault rate.

The invention discloses a desk safety and inspection well, comprising well base (1) set at the bottom of inspection well, well cylinder, well seat (4) and well cover (6). Its well cylinder is divided into fixed well cylinder (2) and active well cylinder (3). The fixed well cylinder (2) is fixed on the well base (1) and presetting active well cylinder (3) is set on the fixed well cylinder (2) vertically. Pre-buried well ring (11) is set on the well seat (4), which is covered on the active well cylinder (3) flatly. Under the well cover (6) there is a desk (5), which covers on the active well seat (3). The well cover (6) is set in the well ring (11) of well seat (4). The well cover (6) and desk (5) are locked together by screw cap (3) and screw bar (9). The inspection well in the invention can solve the repairing problem when inspection well goes down or declines under pressure and the well cover is connected with the well seat by hinge so that it is opened freely and not easy to be stolen. Abnormal well cover is not easy to be turn out when it is extruded by wheel. If one well cover is lost, the reflectorized paint on the desk can take a caution to foot passenger or traveling crane so as to avoid the traffic accident.

The present invention provides a connector which is constructed for keeping a FPC without other components and obtaining a stable connection. After the FPC (80) is inserted, through the action of a rotating component, a contact part (22) of a first contactor or a second contactor, or a sawtooth-shaped extension part which is opposite with the contact part (22) and is displaced from the contact part (22) or a projection (40) that is configured at the other side of a U-shaped member is held. Therefore, the FPC is sandwiched and can not be easily pulled out.

The invention discloses a knapsack type dust collector. A knapsack device is formed by fixing a waist belt and shoulder belts on a backing plate through tying belts; the backing plate is an integral formed by fastening an rabbet on the backing plate and a groove on the upper end of a large cylinder; a dust collecting device is formed by the matching of a paper filter bag and an advanced filter fixed on a motor cavity, wherein the paper filter bag is connected with an air inlet pipe and placed into a bag dust filter; and a strap joint is an integral formed by fixing a transparent cover connected with the air inlet pipe and a cover connected with a warped switch. The knapsack type dust collector has a filtering ratio up to 99.90 percent, and is particularly suitable for hospital, laboratories and other places special cleaning requirements. The invention can be conveniently put on the shoulders, is labor-saving and convenient, is more convenient for long-time operation, is particularly suitable for working in narrow spaces on planes, high-speed railway locomotives, deluxe coaches and other transportation vehicles, and reduces labor intensity. Moreover, dust can be observed directly through the transparent cover, which is convenient for real-time processing and avoids secondary pollution, and the strap joint is connected with the dust collecting pipe and a dust collecting head through a connection pipe capable of rotating omnidirectionally, thereby avoiding pipe-winding phenomenon.

The invention belongs to the technical field of gas purification and discloses a tritium gas purification system. The system comprises a tritium gas introduction system which is connected with each other or disconnected via valves, a circulation separation system and a tail gas monitoring system. The tritium gas introduction system comprises a vacuum pump, a cold trap, a buffer bottle, a vacuum gauge and a bottle for storing tritium and uranium to be purified. The circulation separation system comprises two flow-type uranium beds, a tritium-storing uranium bed and a circulating pump, wherein the two flow-type uranium beds and the tritium-storing uranium bed are serially connected through pipelines and are all provided with an electric-heating device. The two flow-type uranium beds respectively adsorbs impurity gas other than tritium gas or helium gas, and stores the tritium gas and releases the tritium gas after storing the tritium gas; the tritium-storing uranium bed stores the released-purified tritium gas and is connected with a tail gas tank of the tail gas monitoring system through pipelines; the tail gas monitoring system comprises the tail gas tank, a tail gas monitoring pressure meter and the circulating pump. The purification system has advantages of almost 100% recovery rate of tritium gas and more than 99% purity of tritium gas.

The invention relates to an assembled buckle structure which comprises a substrate (2) to be inserted in a decorative strip (1). The lower end surface of the substrate (2) is provided with a clamping part which is clamped in a mounting hole (31) of a counterpart piece (3). The assembled buckle structure is characterized in that the clamping part comprises a plurality of elastic strips (4) which extend downwards and are arranged at intervals, the elastic strips are encircled into a loop matched with the shape of the mounting hole on the counterpart piece, and the lower part at the outer side of each elastic strip is provided with clamping pins (41) which protrude outwards and gradually expand from bottom to top; and a bolt (5) is inserted from bottom to top in the space encircled by the elastic strips, and the peripheral surface of the bolt acts on the inner end surfaces of the elastic strips so that the elastic strips keep the outwards bracing trend. Because of the favorable elasticity of the elastic strips, the interference between the clamping pin size and the mounting hole is smaller, the elastic strips can be inserted in the mounting hole by only needing small inserting force, and the peripheral surface of the bolt can brace the elastic strips outwards so that the elastic strips are clamped in the mounting hole and hardly drawn out.

The invention discloses a rotary type unfolding bolt fastener for single-side installation of a component. The rotary type unfolding bolt fastener is provided with a screw rod and a sleeve cylinder, the end part of the screw rod is spaced with three convex rotary shafts at the intervals of 120 degrees, the sleeve cylinder is matched with the screw rod, and is spaced with three convex rotary shafts at the intervals of 120 degrees which are matched with rotary sheets, the tail section of the screw rod is provided with threads which are matched with a screw cap, the middle section of the screw rod is provided with a polished rod, and the front end of the screw rod is provided with a support head; the support head is spaced with the rotary shafts at the intervals of 120 degrees and the six rotary unfolding type rotary sheets in two layers, each layer is provided with three rotary sheets, and the rotary sheets are matched with the rotary shafts on the sleeve cylinder; when the rotary sheets are unfolded, the diameter of the support part of the part, protruding out of the sleeve cylinder, of each rotary sheet is greater than the outer diameter of the sleeve cylinder and the diameter of the tail part, so as to realize the support function; when the fastener is installed, the screwing of the screw cap is locked by an inner screw rod, so the six rotary sheets are unfolded, and the single-side tightening is realized. The rotary type unfolding bolt fastener has the advantages that the installation of a bolt is completed at one side, and the single-side operation of the bolt is completed.

The invention relates to a steel-prefabricated concrete composite beam and a manufacturing method thereof. The composite beam includes a prefabricated reinforced concrete slab 1, a prefabricated reinforced concrete slab 2 and an H-shaped steel beam, a prefabricated reinforced concrete slab 1, a prefabricated reinforced concrete slab 2 and an H-shaped steel beam. The steel beams are connected by detachable shear connectors. The invention not only has strong shearing resistance, but also is easy to disassemble.

A copper / rare earth oxide / carbon aontact, whose material composite ratio(mass percentage) is: carbon 0.1-2.0, ytterbium trioxide or samarium trioxide 0.1-15, alloy 0.05-2.0 and copper the other, uses method of powder metallurgy and electroplating sediment to produce and the contact produced has excellent resistance to oxidation and electric arc burnt.