45results about How to "Reduce radial temperature gradient" patented technology

The invention discloses a preparation device and application of a silicon carbide single crystal, and belongs to the field of preparation of single crystals. The preparation device of the silicon carbide single crystal comprises a crucible, a charging basket and a rotary lifting unit, the crucible comprises an upper crucible and a lower crucible; wherein the charging bucket comprises a bucket bodyand an opening part, the bucket body is arranged in the lower crucible, the opening part is rotatably connected with the upper crucible, and the charging bucket and the upper crucible form a growth cavity for preparing the silicon carbide single crystal by a physical vapor transport method; an isolation cavity is formed between the charging bucket and the lower crucible; the rotary lifting unit drives the charging bucket to rotate and lift relative to seed crystals. According to the preparation device, the charging bucket is accurately and stably located in the center of the crucible servingas a heating body in the rotary lifting process, the interior of the charging bucket is heated evenly due to the consistent temperature of the sections of the charging bucket in all directions, then the defects that carbon inclusions are generated in the prepared silicon carbide single crystal and the like are overcome, and the quality of the prepared silicon carbide single crystal is improved.

The invention relates to a thermal field structure used in a polycrystalline silicon ingot furnace for controlling a crystal growth interface. The structure comprises an upper furnace body and a lower furnace body; a heat isolation cage and an upper heat insulation plate are arranged in the upper furnace body, and a bottom heat insulation plate is arranged in the lower furnace body; a support rod supports a graphite coagulating assistant block in the heat isolation cage; L-shaped heat insulation plates are hung upside down on the edges of two ends of the graphite coagulating assistant block; a side heat insulation plate is mounted at the bottom on the inner wall of the heat isolation cage. The heat isolation cage, the side heat insulation plate, the bottom heat insulation plate and the upper heat insulation plate form a sealed cavity during heating; and the side heat insulation plate keeps a clearance of 5-30mm with the L-shaped heat insulation plates during the crystal growth. The thermal field structure enables the crystal interface to always maintain a relatively-ideal plane state during the ingot growth of polycrystals, thereby enabling the radial resistivity of cast polycrystalline ingots to be more uniform, improving the uniformity in the electrical performance of a silicon wafer, and reducing the gradient for radial temperature of the crystals. Therefore, the thermal stress of the crystals can be reduced, the defects of the crystals can be reduced and the conversion efficiency of the battery is improved.

The invention discloses a heat pipe even-temperature heat dissipation device used for a vehicle disc brake. The device comprises a brake disc composed of brake flanges arranged oppositely. Heat pipe arrays are arrayed on the opposite faces of the two brake flanges respectively in an annular shape, and the heat pipe arrays are fixed to the brake flanges in a surface contact mode through heat pipe grooves formed in the brake flanges. According to the device, it is unnecessary that an extra auxiliary power source is used for maintaining operation of heat pipes, extra motion components do not need to be arranged inside the brake disc, in this way, reliability is high, and it is avoided that the motion components fail because of abrasion, collision and others. The structure of an existing brake disc is sufficiently used, the heat pipe grooves are formed in air ducts between the opposite surfaces of the brake flanges, people do not need to change the overall structure of the brake disc, adaptability is high, the technology is simple, and the cost is low. According to the device, the technology means is simple and easy and convenient to implement, the even-temperature performance of the brake disc is good, the surface average temperature and the transient temperature are low, the structure is simple, the reliability is high, and installing is convenient.

The invention discloses a graphite resistance heating SiC crystal growth furnace. The graphite resistance heating SiC crystal growth furnace comprises a furnace chamber, a crucible and a heating unit,wherein an upper flange cover and a lower flange cover are respectively arranged at the upper end and the lower end of the furnace chamber; an upper furnace cover is arranged on the upper flange cover; the crucible is arranged in the furnace chamber; a seed crystal cover is arranged on the upper part of the crucible; both of heat-insulating felts are arranged above the crucible and below the crucible; at least one section of graphite heating units are arranged on the outer part of the crucible from bottom to top; the graphite heating units are used for heating graphite resistance; each section of the graphite heating units is separately provided with a corresponding heating power control device; a corresponding heat insulating layer is arranged at the periphery of each section of the heating units. The growth furnace adopts multi-section graphite resistance heating, so that control of a crystal growth temperature field can be conveniently carried out, including a temperature gradientof a growth interface forward position and length of a growth constant-temperature zone. The growth furnace can be used for growing large-sized SiC crystals with high quality, so that the diameter andthe thickness of a product can be greatly improved, a utilization ratio of the SiC crystal is greatly improved, and the growth cost of the SiC crystal is reduced.

The invention provides a single crystal silicon growth control method. The 700-920 DEG C zone of a silicon crystal rod is cooled by adopting a reflecting and cooling device, the length of the zone can be smaller than 200 mm, and the speed of lifting and pulling the silicon crystal rod is greater than 1.12 mm/min, so that the standing time of the crystal rod in the temperature interval is less than 180 minutes to avoid the formation of OSF defects. Radiating infrared rays of a molten silicon fluid are reflected by adopting a semi-parabolic arc-shaped reflection surface to irradiate the side face of the silicon crystal rod at the growth interface position and reduce the cooling speed of the lateral surface, so that the temperature gradient of the center and the surface of the growth interface position of the silicon crystal rod is reduced, and an oxygen element and doped elements on a wafer are radially and evenly distributed. The rays of a high-temperature crucible wall are reflected by adopting a smooth and clean surface to avoid the influence on the crystal rod.

The invention discloses a seeding and shoulder expanding device and technique for single crystal rods and a single crystal furnace and belongs to the technical field of production of single crystal silicon. The seeding and shoulder expanding device for the single crystal rods comprises a hammer located above a crucible, wherein a conical reflection cover is fixed on the side wall of a connecting end, close to a seed crystal, of the hammer, the cone vertex angle is 150-180 degrees, and the conical surface faces molten silicon; the single crystal furnace comprises the seeding and shoulder expanding device for the single crystal rods; the seeding and shoulder expanding technique for the single crystal rods is performed by use of the single crystal furnace and comprises steps as follows: seeding: the rotating speed of the crucible is 8-12 rpm, the rotating speed of the seed crystal is 10-13 rpm, the seeding length is 120-200 mm, and the diameter of fine crystals is 4-8 mm; shoulder expanding: the rotating speed of the crucible is 10-12 rpm, the rotating speed of the seed crystal is 10-13 rpm, and the shoulder expanding pulling speed is 0.5-0.8 mm/min. The seeding and shoulder expanding success rate can be greatly increased, and the seeding and shoulder expanding time can be shortened.

The invention relates to the single crystal high-temperature alloy solidifying technique, including case, heating set, sample clamping framework and DC electric field generating set. The clamping framework is set under the case, composed of two clamping bars set on the bracket, one end of each clamping bar linked with the rotation shaft on the bracket, the other end linked through fastener, and the outer side of each clamping bar installed with tension spring, the other end of each tension spring fixed on the bracket, and the bracket opened with a through hole to make the sample pass through; the generating set is a close loop, formed by setting a programmable functional module in series between one end of the sample and one pole of the voltage-stailized source, and connecting the other end with the other pole through the clamping tool.

The invention discloses a raw material sintering process of silicon carbide crystals grown by a PVT (physical vapor deposition) method. The silicon carbide raw material is led to the sintering processwith the PVT method, a sintering fixture is designed, the silicon carbide is sintered through the previously designed sintering fixture, and the silicon carbide crystals are grown by the PVT method.The raw material sintering process has the advantages that the silicon carbide raw material forms a certain structure through sintering of the silicon carbide raw material, crystallization of the silicon carbide raw material is weakened, densification degree of the silicon carbide raw material is lowered, impurities carried in the silicon carbide raw material can be removed during sintering, fullsublimation and stable growth speed of the silicon carbide crystals by the PVT method can be effectively controlled and maintained, and the yield of the utilization of the silicon carbide raw materialand the silicon carbide crystals is increased.

This invention relates to a method for preparing heterovalent ions-doped high-luminescence-yield lead tungstate crystal and its preparation method. The high-luminescence-yield lead tungstate crystal is doped with F- 100-8000 ppm, Sb3+ 100-5000 ppm, and Mo6+, V5+, Nb5+, Zr4+, and Ti4+ 0-10000 ppm, and is prepared via modified Bridgman method by using platinum crucible. The method can be used for preparing several strands of lead tungstate crystals in one process, and is suitable for mass production. The obtained heterovalent ions-doped high-luminescence-yield lead tungstate crystal has such advantages as rapid attenuation and high luminescence yield.

Described is a cyclone separator comprising a cyclone housing (1), a discharge duct (5) and a central tube (3) for diverting gases, said central tube (3) extends axially into the cyclone housing (1) and being composed by a number of segments (3a) which are suspended on a supporting element (15) provided in the area between the cyclone housing (1) and the discharge duct (5). The cyclone separator is peculiar in that it comprises a number of carrying means (17) which are evenly distributed and fixed to the inner side of the cyclone housing (1) and/or the discharge duct (5), and in that the supporting element (15) comprises an annular disc which is loosely fitted on top of the carrying means (17) and having an outer diameter which is smaller than the inner diameter of the cyclone housing (1) and/or the discharge duct (5) so that a clearance (18) is provided between the annular disc (15) and the cyclone housing (1) and/or the discharge duct (5). Hereby is obtained a significant reduction in the heat transmission from the supporting element to the cyclone housing and/or the discharge duct so that the radial temperature gradient in the supporting element is reduced with an approximately uniform temperature over the radial cross section of the element. Hence the thermal stresses in the supporting element will be substantially reduced. This is mainly ascribable to the reduction in the contact area between the supporting element and the cyclone housing and/or the discharge duct.

The invention discloses a silicon carbide crystal growth crucible for increasing utilization rate of power sources and solves the problems that utilization rate of silicon carbide power sources is low and average growth rate of crystal is low. The silicon carbide crystal growth crucible comprises a crucible body. A cavity of the crucible body is divided into a plurality of split areas for containing silicon carbide power sources horizontally.

The invention provides a preparation method and a growth device of an N-type silicon carbide crystal. The method comprises the following steps: (1) placing a raw material in a high-temperature area of a crucible, placing a seed crystal in a low-temperature area of the crucible, recessing the outer wall of the top of the crucible inwards to form an annular gas groove, placing the assembled crucible in a furnace body of a crystal growth furnace, and enabling the annular air groove to be close to a vent hole of the furnace body; and (2) in a crystal growth stage, introducing nitrogen source gas into the furnace body through the vent hole, controlling crystal growth temperature and crystal growth pressure, and enabling the N-type silicon carbide crystal to grow on the seed crystal. The annular gas groove is close to the vent hole of the furnace body, the introduced gas can flow along the annular gas groove, a gas flow speed is high, the gas is diffused into the crucible, heat transmission away from the central axis in the crucible is accelerated, the radial temperature gradient of the crucible is reduced, and crystal growth quality is improved.

The invention provides a plastic extruder, and relates to the technical field of plastic extrusion devices. The plastic extruder comprises a base, a charging barrel arranged on the base, a feeding port formed in the top of one end of the charging barrel, an extrusion port formed in the other end of the charging barrel, a screw arranged in the charging barrel, and a motor arranged on one side of the charging barrel and connected with the screw, wherein the screw is a taper angle-shaped screw, and sequentially comprises a feeding section, a plasticizing section, a compression section, an exhaust section, an extrusion section and a hook-shaped screw head from the motor to the extrusion port. The hook-shaped screw head forms a material channel from the surface of the screw to the core part of the screw, the shearing rate of molten material at the section is increased, and therefore the radial temperature gradient is reduced, the phenomenon that the material is retained and decomposed at the section is obviously relieved, and the mixing efficiency is improved.

The invention discloses a liquid-phase growing silicon carbide seed crystal shaft device, and belongs to the field of novel material preparation. The device comprises a moving connection part, a heat resistant part and a graphite platform which are detachably connected in sequence, wherein a seed crystal is connected to the other end of the graphite platform; the heat resistant part is a heat resistant material of which the thermal conductivity is lower than that of graphite and does not react with silicon steam; the seed crystal can be square, round, polygonal or the like; the graphite platform is the same as that of the seed crystal in shape, and is not smaller than the seed crystal in size; the radial size of the heat resistant part is not smaller than those of the moving connection part and the graphite platform, or the radial size of the heat resistant part is not larger than those of the moving connection part and the graphite platform; each of the two ends of the heat resistant part is of an internal thread structure and each of the moving connection part and graphite platform connected with the heat resistant part is of an external thread structure, or each of the two ends of the heat resistant part is of an external thread structure and each of the moving connection part and graphite platform connected with the heat resistant part is of an internal thread structure.

The invention relates to the field of turbines, in particular to a cooling method and structure of a cantilever type supercritical carbon dioxide turbine, main sealing gas for dry gas sealing is injected from a first gas channel on a dry gas sealing shell, and the sealing gas is cooling gas which sequentially flows into the shell along a second gas channel and a first gap between a high-speed shaft and a splitting ring; and one path of cooling gas is exhausted to an exhaust flow channel in the shell through an exhaust hole of a baffle, the other path of cooling air is exhausted to the exhaust flow channel in the shell through a second gap formed by the baffle and a turbine disc, in addition, after the splitting ring and a middle shell are split into two parts, the radial temperature gradient on each part is reduced, therefore, the temperature stress on each part is reduced, the turbine can be better cooled, and the strength reliability of a unit is ensured.

The invention discloses a graphite thermal-field single crystal growth device for preparing silicon carbide crystals, belonging to the technical field of silicon carbide single crystal preparation and crystal growth. The graphite thermal-field single crystal growth device comprises a sealing cavity, a heating structure, a heat preservation structure, a temperature adjusting structure, a crucible and a temperature measuring mechanism, wherein the heat preservation structure is arranged in the sealing cavity; the heating structure is arranged in the heat preservation structure; the temperature measuring mechanism is arranged on the sealing cavity; the temperature adjusting structure is arranged in the heat preservation structure, and a crucible and a seed crystal support are arranged in the heat preservation structure; the heating structure is used for heating the bottom and the top of the crucible and carrying out axial and radial temperature control on the crucible; the temperature measuring mechanism is used for respectively measuring the temperatures of the top and the bottom of the crucible; the heat preservation structure is used for carrying out heat preservation on a thermal field of the whole cavity, so heat loss of the crucible can be reduced, and accurate temperature control on each part of the crucible is realized; the temperature adjusting structure can reduce the radial temperature gradient of the crucible; and therefore, the radial temperature gradient and the stress gradient of the crystal in the growth process of the silicon carbide single crystal are reduced, the defects of crystal growth can be reduced, and the quality of the crystal is ensured.

The invention relates to a cylinder liner arrangement for a reciprocating internal combustion engine and a cooling method. The cylinder liner arrangement comprises a cylinder liner, in which a piston is installed, the factory and installed state between a top dead center and a bottom dead center so along a cylinder axis of the cylinder liner reciprocally disposed forth that a top of the piston delimits, together with a running surface of the cylinder liner and on the cylinder liner arranged in the cylinder cover a combustion chamber. The cylinder liner comprises a liner cooling system for cooling the cylinder liner by means of liner cooling fluid and the cylinder cover comprises a cover cooling system for cooling the cylinder cover by means of a cover cooling fluid, According to the invention, the liner cooling system in such a manner decoupled from the cover cooling system that a flow communication between the liner cooling fluid and the cover cooling fluid is controlled or regulated, or that the flow communication between the liner cooling fluid and the cover cooling fluid is prevented.

The invention discloses a burner for growing crystals by a flame fusion method. The burner comprises a conical feeding port, a central pipe, a hydrogen inlet, an external oxygen inlet, a hydrogen ring-shaped pipeline, an external oxygen ring-shaped pipeline, a crystal growing chamber and a crystal growing base, wherein the conical feeding port is connected with the central pipe; powder and oxygenare fed into the central pipe from the conical feeding port; the central pipe is externally provided with the hydrogen ring-shaped pipeline; hydrogen is filled into the hydrogen ring-shaped pipeline by the hydrogen inlet connected with the hydrogen ring-shaped pipeline; the hydrogen ring-shaped pipeline is externally provided with the external oxygen ring-shaped pipeline; oxygen is filled into theexternal oxygen ring-shaped pipeline by the external oxygen inlet connected with the external oxygen ring-shaped pipeline; the tail ends of the central pipe, the hydrogen ring-shaped pipeline and theexternal oxygen ring-shaped pipeline are respectively communicated with the crystal growing chamber; the crystal growing base is arranged in the growing chamber. The burner disclosed by the inventionhas the advantages that the radial and axial pressure distribution of the burner can be greatly reduced, so that the radial distribution of the oxygen is more uniform, oxygen vacancy of the crystal is reduced, the size and the uniformity of crystal growth are improved and the crystal quality is improved.