286 results about "Liquid nitrogen container" patented technology

Mobile fire-fighting systems and a method of producing breathable fire-suppression compositions are provided for extinguishing fires in buildings, and other human occupied structures, being also effective in suppressing fires under ruins of collapsed buildings. The systems employ a transportable high-pressure container having the breathable composition or nitrogen gas, or a liquid nitrogen container, vaporizer and a mixing chamber, wherein a vaporized nitrogen gas is mixed with an ambient air in order to produce said breathable fire-suppression composition. Refilling stations are provided for refilling the mobile systems with said composition, nitrogen gas or liquid nitrogen, all being generated at site from the ambient air. The method of producing said composition at a fire site employs mixing of nitrogen gas with ambient air or, alternatively, vaporizing of liquid nitrogen in necessary quantities and mixing it with ambient air in provided proportions. A method of delivery of the breathable fire-suppressive composition inside a building on fire is provided as well. The systems are also suitable for installation as a stationary fire-suppression system for a building or other structure. A breathable fire-suppression composition is provided for use in said mobile systems, said composition having an oxygen content below 16% or from 10% to 12% for the majority of civil applications.

The invention discloses a liquid nitrogen container and a cryogenic vial pick-and-place device. The liquid nitrogen container comprises a container body, and further comprises a rotary disc, a cryopreservation frame, a central shaft and a driving assembly, wherein an opening is formed in the container body; the rotary disc is arranged in the container body; the cryopreservation frame is supported by the rotary disc and comprises a plurality of layers of placement faces; the included angle between each placement face layer and the rotary disc is 40-60 degrees; the central shaft is perpendicularly arranged with and fixedly connected with the rotary disc; the driving assembly is electrically connected with the central shaft and used for driving the central shaft to rotate; and the central shaft is used for driving the cryopreservation frame to rotate through the rotary disc to reach the opening of the container body. By adoption of the liquid nitrogen container and the cryogenic vial pick-and-place device, the workload of operating personnel is reduced, the error rate of manual picking of cryogenic vials is lowered, and the potential safety hazard for the operating personnel is avoided. The liquid nitrogen container and the cryogenic vial pick-and-place device are particularly suitable for the work of picking cryogenic vials in a high-capacity biological sample bank, and meet the technical requirement for storage in the high-capacity biological sample bank.

The invention discloses a high-low temperature dynamic cold-hot circulation thermodynamic test system suitable for mechanics performance testing under a high-low temperature environment. A test box adopts a design of an inner cavity and an outer cavity; inner and outer cavity baffles are provided with four air outlets from top down and air suction holes in the center; the test box further comprises an optical strain observation window, a defrosting air heater and a multi-point direct-current illumination source; and in addition, the test system further comprises a dual-output PID (Proportion Integration Differentiation) controller, a DIC (Digital Image Correlation) full strain measurement instrument and an automatic switchover liquid nitrogen refrigerating system. According to the high-low temperature dynamic cold-hot circulation thermodynamic test system, the defects that the conventional thermal steady state test system has no thermal transient state and thermal circulation functions and liquid nitrogen cannot be fed without interruption due to limitation of liquid nitrogen container volume on low-temperature refrigeration are solved, and the technical problems of interference and the like of high-temperature hot wave impact and low-temperature frost fog on full strain measurement are solved at the same time, so that the purposes of obtaining the mechanical performance of a test material under the high-low temperature environment in the processes of thermal steady state, thermal transient state, cold-hot circulation and the like and synchronously measuring a sample strain field are achieved.

The invention discloses an electro-plastic two-roll mill of a low-temperature liquid nitrogen cooling medium. A rack (6) at the entrance of the two-roll mill is provided with two dragging tracks (12 and 12'); a track groove between the two dragging tracks (12 and 12') is internally provided with a feeding clamp (13); a cooling tank (14) is arranged below the rear ends of the two dragging tracks (12 and 12'); the rack (6) at the entrance of the two-roll mill is provided with a delivery guide (16); a collecting tank (4) is arranged below the delivery guide (16); a liquid nitrogen container (9) is arranged on a bracket (10) for fixing the rack (6); the negative electrode of an impulse power source (1) is connected with the upper plywood of the feeding clamp (13) by a cable (2), and the positive electrode of the impulse power source (1) is connected with a roll electrode (3) by the cable (2). In the rolling process by using the electro-plastic two-roll mill, the low-temperature liquid nitrogen is automatically sprayed on a rolled piece deformation zone; and the rolled piece is in the low temperature environment of minus 160 to minus 70 DEG C before the process of rolling processing, in the process of rolling plastic deformation, and after the process of rolling processing. Hard pulse current vertical to the deformation direction is imported into the rolled piece deformation zone between an upper roller and a lower roller, and the electro-plastic effect is used to reduce the deformation resistance of the rolled piece and improve plastic deformation capacity of the rolled piece, thus obtaining the rolled piece product with serious plastic deformation.

Mobile fire-fighting systems and a method of producing breathable fire-suppression compositions are provided for extinguishing fires in buildings, and other human occupied structures, being also effective in suppressing fires under ruins of collapsed buildings. The systems employ a transportable high-pressure container having the breathable composition or nitrogen gas, or a liquid nitrogen container, vaporizer and a mixing chamber, wherein a vaporized nitrogen gas is mixed with an ambient air in order to produce said breathable fire-suppression composition. Refilling stations are provided for refilling the mobile systems with said composition, nitrogen gas or liquid nitrogen, all being generated at site from the ambient air. The method of producing said composition at a fire site employs mixing of nitrogen gas with ambient air or, alternatively, vaporizing of liquid nitrogen in necessary quantities and mixing it with ambient air in provided proportions. A method of delivery of the breathable fire-suppressive composition inside a building on fire is provided as well. The systems are also suitable for installation as a stationary fire-suppression system for a building or other structure. A breathable fire-suppression composition is provided for use in said mobile systems, said composition having an oxygen content below 16% or from 10% to 12% for the majority of civil applications.

The invention discloses a preparation method of a graphene dispersion liquid. The preparation method comprises the following steps: (1) dispersing graphene oxide into a solvent A to obtain a graphene oxide dispersion liquid; (2) spraying the graphene oxide dispersion liquid into a liquid nitrogen container and carrying out quick freezing treatment to obtain a quickly frozen product of the graphene oxide dispersion liquid; (3) adding the quickly frozen product of the graphene oxide dispersion liquid to a reaction kettle with a solvent B so that the temperature of the system naturally rises to the room temperature; (4) adding an acidity regulator to the system to regulate the pH to the range from 4.00 to 11.00 at the room temperature; (5) adding a reducing agent to the system for solid-liquid separation to obtain a solid material; and (6) adding the solid material to a solvent C to obtain the graphene dispersion liquid. The preparation method of the graphene dispersion liquid, disclosed by the invention has the beneficial effects that the obtained graphene dispersion liquid is black thick slurry, high in electrical conductivity, excellent in heat stability and easy to disperse, and the graphene exists completely as a single-layer sheet structure. The preparation method of the graphene dispersion liquid, disclosed by the invention, is simple to operate, high in yield, low in cost and suitable for large-scale production.

A low-temperature abrasive jet machining device is characterized by comprising an abrasive jet generation system, a cooling system and a machining system. The abrasive jet generation system mainly comprises a nitrogen cylinder (1), a grinding bin (2), a gas-powder mixing device (15), an abrasive jet pipe (8) and an abrasive jet nozzle (14). The cooling system mainly comprises a self-pressurizing liquid nitrogen container (5), a liquid nitrogen safe valve (4) and a cooling pipe (16); and one end of the cooling pipe (16) is connected with the self-pressurizing liquid nitrogen container (5) through the liquid nitrogen safe valve (4), and the other end of the cooling pipe (16) is connected with a composite nozzle (11). The abrasive jet pipe (8) and the abrasive jet nozzle (14) connected with the abrasive jet pipe (8) are both installed in the cooling pipe (16) so as to achieve cooling in the flowing process of abrasives, and while the abrasives are ejected out of the abrasive jet nozzle (14), the abrasives are mixed with low-temperature nitrogen entering the composite nozzle (11) through the cooling pipe (16) and then are ejected to a workpiece (13) through an ejection port of the composite nozzle (11). According to the low-temperature abrasive jet machining device, the structure is simple, machining efficiency is high, and the problem of low-temperature quick machining of a hydrophobic polymer is solved.

The invention discloses a full-automatic liquid nitrogen filling device and a control method thereof. A temperature sensor (7) is arranged in a liquid nitrogen container (3) in a high temperature superconducting coil, and a liquid nitrogen delivery pipe (5) is arranged between a liquid nitrogen dewar (1) and the liquid nitrogen container (3) in the high temperature superconducting coil. When liquid nitrogen in the liquid nitrogen container (3) in the high temperature superconducting coil achieves the low position, a liquid adding controller (2) delivers liquid nitrogen low position temperature marginal value information according to the temperature sensor (7) to be instruments to start up a miniature pump (4) to open a switch, the miniature pump is opened, and air presses the liquid nitrogen in the liquid nitrogen dewar (1) into the liquid nitrogen container (3) in the high temperature superconducting coil. When liquid nitrogen in the liquid nitrogen container (3) in the high temperature superconducting coil achieves the high position, the liquid adding controller (2) delivers liquid nitrogen high position temperature marginal value information according to the temperature sensor (7) to be instruments to start up the miniature pump (4) to close a switch, and liquid nitrogen adding is stopped. The full-automatic liquid nitrogen filling device can automatically or manually add liquid, and is free of influences of magnetic resonance magnetic fields and electric fields.

The invention discloses a vertical container used for storing low-temperature liquid. The vertical container comprises a shell provided with a seal cavity, an inner container mounted in the cavity and used for storing the low-temperature liquid and a cold source container used for storing liquid nitrogen; the outer side of the inner container is coated with a liquid nitrogen cold shield, a liquid nitrogen cooling pipe is arranged on the liquid nitrogen cold shield, and the liquid nitrogen cooling pipe and the cold source container are communicated to form a liquid nitrogen circulation loop; and the vertical container mainly adopts a heat insulation manner combining vacuum multi-layer heat insulation with the liquid nitrogen cold shield to reflect the excellent heat insulation performance. An inner container used for storing liquid nitrogen media is arranged in the vertical container, the independent liquid nitrogen cold source container and the independent liquid nitrogen cold shield are arranged, through dissipation of liquid nitrogen in the cold source container, the heat wall temperature of the liquid nitrogen container is reduced to 77 K from 300 K, the radiant heat flux is reduced to 1 / 150 to 1 / 200 of the original flux, and therefore the aim of greatly reducing the daily evaporation rate loss of the container is achieved.

The invention relates to a cryogenic pulverizer and its working method, comprising a motor, a hopper, a material pre-cooling room, a material freezing room, a low-temperature mill, an induced draft fan, a cyclone separator, a bag filter, a liquid nitrogen tank and a compressor. Machine, the cryogenic pulverizer of the present invention and its working method, use liquid nitrogen to cool and freeze the material to be pulverized so as to achieve the brittleness required for the pulverization of the material, rich in resources and easy to separate, colorless, odorless and non-toxic gas, to avoid In addition, nitrogen is also a good anti-oxidant, which can prevent the finished powder material from being oxidized and deteriorated, and realize the recycling of nitrogen. In addition, the cooling capacity of the finished powder material is fully utilized to reduce energy consumption. save resources.

The storage comprises, from the bottom to the top, a low temperature storage zone, for storing the samples, a handling zone, housing at least part of an automatic transport device, and an access zone, where the user can enter for maintenance. A separating wall consisting of removable panels insulates the access zone, for the rooms below it. A peripheral housing, contains a peripheral chamber for temporarily storing the samples at slightly higher temperatures. A liquid nitrogen container, is used to feed dry gas to the storage zone and to maintain it under slight overpressure for preventing the entry of moisture.

The invention provides a resonant coupling wireless power transmission system adopting a superconducting coil and an implementation method thereof. The resonant coupling wireless power transmission system comprises a high-frequency power source, a transmitting coil, a receiving coil and a liquid nitrogen container, wherein at least one of the transmitting coil and the receiving coil is made of high-temperature superconducting materials; the high-temperature superconducting coil is positioned in the liquid nitrogen container; and the high-frequency power source is connected with the input end of the transmitting coil. The implementation method provided by the invention can be used for making the transmitting coil and (or) the receiving coil by replacing the traditional common materials, such as copper wires and the like, with the high-temperature superconducting materials, thereby greatly reducing the internal resistance of the coils, greatly increasing the transmission power and efficiency, further lengthening the wireless power transmission distance and reducing the sizes of the coils and the resonant working frequency.

The invention discloses a multi-layer low-temperature heat insulation structure arranged in a density-variable mode. The multi-layer low-temperature heat insulation structure arranged in the density-variable mode comprises multiple reflecting layers which are evenly separated into three parts in the thickness directions of the reflecting layers. Different layers of isolating materials are filled among adjacent reflecting layers of each part, wherein the layer density of the multi-layer low-temperature heat insulation structure close to a cold-boundary part is 7.5 layers per centimeter, the layer density of the middle part of the multi-layer low-temperature heat insulation structure is 15 layers per centimeter, the layer density of the multi-layer low-temperature heat insulation structure close to a hot-boundary part is 22.5 layers per centimeter. Compared with the traditional multi-layer heat insulation arrangement mode that the density of the whole structure is 15 layers per centimeter, the arrangement mode of the multi-layer low-temperature heat insulation structure arranged in the density-variable mode ensures that heat insulation performance is improved by 14.3% when being applied to a liquid nitrogen container with the hot-boundary temperature of 353K and the cold-boundary temperature of 77K for heat preservation.

The invention relates to a heat conductivity coefficient measurer of a double-test-piece guarded hot plate for a liquid nitrogen temperature area, comprising a vacuum cover, a guarded hot plate, two liquid nitrogen containers, three temperature sensors, a supporting plate, a sliding structure, a clamping structure and a hanging structure, wherein the guarded hot plate is arranged between the two liquid nitrogen containers; the clamping structure is arranged on the liquid nitrogen containers; the liquid nitrogen containers and the guarded hot plate are fixed on the sliding structure; the sliding structure is connected with the hanging structure; the hanging structure is fixed at the upper end in the vacuum cover; the guarded hot plate and the liquid nitrogen containers are fixed on the hanging structure; and the vacuum cover is welded on the supporting plate. The invention is used for measuring the heat conductivity coefficient of a heat insulating material of the liquid nitrogen temperature area, wherein a testing part is hung on the vacuum cover, and glass fiber reinforced plastics are used as the heat insulating material, thereby liquid nitrogen evaporation is reduced; and a vacuum pumping processing mode is adopted, thus the measurement errors brought by heat conduction and convective heat exchange of air are effectively reduced.

An environmental simulation device for high / low temperature fatigue property testing is composed of a high-temperature-resisting multi-step circular shaft adapter, a temperature control water cooler, a high-temperature-resisting five-hole slot type clamp, a positioning pin, a bolt, an environment box and a liquid nitrogen container, wherein the high-temperature-resisting multi-step circular shaft adapter is connected with the temperature control water cooler through a water inlet pipe and a water outlet pipe, one end of the high-temperature-resisting five-hole slot type clamp is installed on the adapter, and the other end of the high-temperature-resisting five-hole slot type clamp positions a sample through the positioning pin and is fixedly connected with the sample through the bolt with threads; the high-temperature-resisting five-hole slot type clamp and the sample clamped by the high-temperature-resisting five-hole slot type clamp are wrapped in the environment box, and the liquid nitrogen container is connected with the environment box. Through reasonable and ingenious matching and connection of sub-systems, high / low temperature environment simulation for fatigue property testing can be achieved easily, practically and accurately, and technical support and means are provided for high / low temperature fatigue property testing.

The invention discloses a method for preparing porous ceramic microspheres with different pore structures and a spraying and freezing device. The method comprises the following steps: preparing ceramic slurry at first; spraying the slurry in a controllable ring-shaped temperature field to be frozen, collecting the frozen particles to freeze and dry, rising the temperature to degrease, rising the temperature again to sinter to obtain a porous ceramic microsphere with a pore structure, and controlling the ring-shaped temperature field to obtain porous ceramic microspheres with different pore structures. The spraying and freezing device comprises a sprayer and a freezing device, wherein the freezing device takes a cylindrical liquid nitrogen container as the main body; the cylindrical liquid nitrogen container comprises a large-diameter cylinder and a small-diameter cylinder, which are concentric; the area between the large-diameter cylinder and the small-diameter cylinder is closed; a plurality of baffles are arranged in the area between the large-diameter cylinder and the small-diameter cylinder. The method is simple to operate, and the porous ceramic microspheres with uniform sizes, high degrees of sphericity and controllable pore structures can be prepared through the method, and the device has a simple structure, is strong in practicability, and can control the pore structures of the porous ceramic microspheres through controlling the temperature field.

A liquid nitrogen low-temperature system for a superconducting current limiter belongs to the field of low-temperature engineering and technique. The liquid nitrogen low-temperature system comprises a liquid nitrogen container, a liquid nitrogen valve, a liquid nitrogen refuel valve, a safety valve, a valve cap, a test Dewar, a thermal insulation layer, a rupture disk, a deflation valve, a flow meter, a vacuum measurement gauge, a pressure difference sensor, a pressure sensor, a support part, a pumping valve, a vacuum pump, a superconducting current limiter, a control circuit, a temperature sensor and a discharging air pipe. In the invention, the system adopts the liquid nitrogen as the cooling working medium; the superconducting current limiter for the test is placed in the test Dewar; switching between the superconducting state and superconducting loss state of the superconducting current limiter can be realized through the control circuit; and the pressure, pressure difference and temperature measured by the pressure sensor, the pressure difference sensor and the temperature sensor, and the quality flow of the gasified nitrogen in the superconducting loss state measured by the flow meter are inputted into a computer, so as to evaluate the refrigeration wastage of the low-temperature system of the superconducting current limiter, and study the influence of the bubbles exerted on the low-temperature system pressure intensity when superconducting current limiter is abnormal. The low-temperature system has the advantages of simple structure, good economical efficiency, and favorable safety.

Disclosed is a sample storage apparatus in that a multilayered rotary table is formed in a liquid nitrogen vessel, so that a plurality of sample storage boxes is stored in the multilayered rotary table, whereby it can effectively and maximally ensure the space for storing the samples. The sample storage apparatus includes: a rotating axis 100; a rotary table 200 having an upper cylinder portion 210 protruded upward from an upper middle portion thereof and allowing the rotating axis 100 to be inserted therein and a lower cylinder portion 220 protruded downward from a lower middle portion thereof and allowing the rotating axis 100 to be inserted therein; at least one partition member 300 for partitioning off an upper surface of the rotary table 200 formed at the upper surface of the rotary table 200; a fixing member 400 coupled to one side of an outer circumference of the lower cylinder portion 220 through a hinge coupling portion 410 and having a lower portion protruded downward from a lower end of the lower cylinder portion 220 and a slanting portion formed at one side of an upper end thereof so as to form a fixing gap angle 430; and a latching member 500 formed along an outer circumference of the upper cylinder portion 210 and having a plurality of insertion holes 510 for allowing a lower end of the fixing member 400 to be inserted therein.

The invention relates to the field of mechanical manufacturing, in particular to a temperature-controllable cryogenic cooling device which comprises a fixture, a heat transfer component and a liquid nitrogen container. The fixture is used for clamping a machined material, the heat transfer component is connected with the fixture, and the liquid nitrogen container is connected with the heat transfer component; liquid nitrogen in the liquid nitrogen container is vaporized, absorbs heat and cools the heat transfer component, the heat transfer component cools the machined material by means of heat transfer, and the machined material is clamped by the fixture. The temperature-controllable cryogenic cooling device has the advantages that a large quantity of heat can be absorbed by the aid of vaporization of the liquid nitrogen, the machined material clamped by the fixture is cooled by the heat transfer component with an excellent heat conducting property, and the heat generated during milling machining can be taken away; an obvious cooling effect can be realized, the lowest temperature of the temperature-controllable cryogenic cooling device can reach the temperature of the liquid nitrogen, and accordingly certain materials which are difficult to machine under room-temperature conditions can be effectively milled.

The invention relates to a toughened glass cooling method and a toughening furnace cooling system. The toughening furnace cooling system comprises a blower for supplying air into a toughening furnace, an air collection box and an air supply channel and further comprises a liquid nitrogen container which is mounted on the air collection box or the air supply channel and used for containing liquid nitrogen, wherein in a glass quenching stage, liquid nitrogen is filled into the air collection box connected with the blower within a short time to perform a quenching process while air is supplied by the blower, so that a mixed cooling medium of air and gasified liquid nitrogen can be formed in the air collection box, and the mixed cooling medium is supplied into the toughening furnace through the air supply channel to quench high-temperature glass in the toughening furnace. According to the invention, the temperature of the traditional cooling medium air in air glass toughening can be greatly lowered, and the installed capacity of the blower can be reduced. Thus, the invention can be used for toughening float glass having a thickness less than 3 mm or producing over-toughened glass.

The simple ultralow temperature method of preserving fish sperm includes the following steps: taking fish sperm, diluting with diluent in 1-5 times, balancing in a refrigerator at 4 deg.c for 20-30 min, adding antifreeze agent in certain concentration, packing in 0.5 mm diameter straw, setting on foamed plastic board over liquid inside a foamed plastic case for 20 min, setting the straw into liquid nitrogen inside the case for 5 min, and transferring into liquid nitrogen container for freeze preservation at the temperature of -196 deg.c. The present invention may be used in field operation of preserving fish sperm, and is fast, simple, high in freeze preserving effect and low in cost.

The invention relates to a freeze-thaw damage experiment device and method for shale through temperature and pressure control of liquid nitrogen. A self-pressurization liquid nitrogen container is connected with a temperature and pressure control device through a low-temperature resistant metal pipe; ultralow temperature liquid nitrogen is contained in the self-pressurization liquid nitrogen container; a high-pressure nitrogen gas bottle is connected with the upper ends of the temperature and pressure control device and a freeze-thaw damage device through a high-pressure gas pipe separately; high-pressure nitrogen is contained in the high-pressure nitrogen gas bottle; the lower part of the temperature and pressure control device is connected with the lower part of the freeze-thaw damage device through the low-temperature resistant metal pipe; and a shale core is arranged in the freeze-thaw damage device and is connected with a data collection system through a low-temperature strain gauge. The freeze-thaw damage experiment device and method have the beneficial effects that shake freeze-thaw damage experiment can be carried out at different temperatures and pressure liquid hydrogen action, the adjustable temperature range is large, the damage degradation condition after contact of a stratum rock and the liquid nitrogen can be really simulated, the experiment method is simple, the experiment error is small, and a scientific evidence and a theoretical basis are provided for development of a shale gas reservoir employing an ultralow temperature liquid fracturing technology.

The invention relates to the field of battery energy storage system security, in particular to the field of power battery security. An emergency refrigerating device for a battery energy storage system adopts liquid nitrogen phase-change refrigeration, and comprises a nitrogen generator, a liquid nitrogen container, a cooling pipe, a cooling valve, refrigerating passages and a pressure release valve. The nitrogen generator is used for nitrogen generation and cooling storage during battery charging. A rechargeable micro battery supplies power for the cooling valve, and the controller is provided with an independent signal collecting and logic processing mechanism without depending on a battery management system (BMS); and the controller comprises a vibration sensor which can sense the accidents such as collision and explosion. A closed refrigerating passage is generally mounted on a heat-dissipation module of the battery, and the heat of the battery is dissipated through the heat-dissipation module. An open refrigerating passage is mounted on the battery, and a plurality of small holes formed in the part, close to the battery, of the pipeline are used for uniformly spraying liquid nitrogen onto the battery. The emergency refrigerating device has the beneficial effects that the liquid nitrogen is used for emergency refrigeration, and can reach the effect of quick cooling, so that thermal runaway of a battery pack is prevented, and a thermal runaway chain reaction is avoided to the maximum extent.

A system for testing the fatigue in a high / low temperature environment comprises a fatigue testing machine, an adapter, a sample clamp, a high / low temperature environment box, locating pins, a liquid nitrogen container and a sample, wherein the sample clamp is installed on the fatigue testing machine through the adapter, the sample is connected with the sample clamp and is located through the locating pins penetrating through the sample clamp and locating holes of the sample, the high / low temperature environment box wraps the sample clamp and the sample inside, the liquid nitrogen container and the high / low temperature environment box are connected to achieve the low temperature environment, wherein the fatigue testing machine, the adapter, the sample clamp, the locating pins and the sample are sequentially connected in series together. The system for testing the fatigue in the high / low temperature environment is simple in structure convenient to operate, and used to test the fatigue property in the high / low temperature environment, and the test result has important significance for defining the fatigue of a material or structure in the complicated meteorological environment.

The invention discloses a low-temperature liquid nitrogen fracturing experiment system under confining pressure. The system is used for simulating the process of high-pressure liquid nitrogen fracturing reservoir rock under the condition of ground stress and researching crack initiation characteristics of rock, fractures formation laws and liquid nitrogen low-temperature assisted rock fracturing effect. The experiment system is composed of three parts, namely a liquid nitrogen supercharging injection apparatus, a liquid nitrogen fracturing experiment apparatus and a confining pressure applying apparatus. The liquid nitrogen supercharging injection apparatus contains an adjustable-speed motor, a vacuum pump and a liquid nitrogen container and a pressure cylinder. The pressure cylinder pumps high pressure liquid nitrogen into a rock sample wellbore for fracturing. Meanwhile, the confining pressure applying apparatus applies radial confining pressure onto a rock sample through hydraulic pressure. A rock sample clamping unit applies axial stress onto the rock sample through mechanical thrust. The system is safe and simple to operate, has high efficiency, can conduct low-temperature liquid nitrogen fracturing experiments under various working conditions, and can be used for fracturing experiments of supercritical CO2, water, oil and other fluids under confining pressure.

The invention discloses a cooling-down humidity-control system which comprises a return air module, an mist spraying module, a dehumidifying module and an air delivery module, wherein the air outlet of the return air module is connected to the air inlet of the mist spraying module; the air outlet of the air spraying module is connected to the air inlet of the dehumidifying module by a ventilating pipeline; and the air outlet of the dehumidifying module is connected to the air inlet of the air delivery module. The system further comprises a water storage tank and a system electric controller, wherein the return air module, the mist spraying module, the dehumidifying module and the air delivery module are respectively connected to the system electric controller; and the system electric controller controls the start and stop of each module. A fan is mounted in the return air module; a high-pressure water pump and a nozzle are mounted in the mist spraying module; a heat exchanger and a liquid nitrogen container are mounted in the dehumidifying module; and the liquid nitrogen container contains liquid nitrogen, which enters the heat exchanger after gasification. By using the cooling-down humidity-control system provided by the invention, not only can temperature and humidity be controlled, but also the system has low operation cost and is environmentally-friendly.

A method for ultralow-temp freeze storage of sturgeon sperm with high activity includes measuring the osmotic pressure of sturgeon sperm, determining the antifreeze protective liquid, preparing it by mixing liquid diluent with DMSO, proportionally mixing sperm with said protective liquid, low-temp balancing, loading in centrifugal tube, lowering temp to -5 deg.C, balancing, putting in liquefied nitrogen at -160- -180 deg.C, balancing, storing it in liquefied nitrogen, and two-step thawing: raising temp for -196 deg.C to -160- -180 deg.C and balancing and thawing by water bath at 38-40 deg.C.

The invention relates to a negative-pressure liquid nitrogen subcooler and a method for liquid nitrogen temperature reduction. The negative-pressure liquid nitrogen subcooler is applied to the field of motor vacuum science and technology and comprises a liquid nitrogen conveying system, a subcooler system, a negative-pressure air exhaust system and a discharge system. Wherein the liquid nitrogen conveying system is used for providing liquid nitrogen for the subcooler system, the negative-pressure air exhaust system is provided with an air temperature type vaporizer which is used for reducing the pressure of the subcooler, gas and nitrogen are discharged by the discharge system, in the subcooler system, a pneumatic control valve is adjusted manually in a long-distance manner, so that liquid level of the liquid nitrogen in the subcooler is kept constant. The method comprises the following steps that: firstly, the liquid nitrogen is filled into a liquid nitrogen container, pressure is adjusted, the liquid nitrogen is filled into the subcooler, and the liquid level of the liquid nitrogen in the subcooler is kept constant; then, the negative-pressure air exhaust system is started, and the liquid nitrogen is cooled through a heat exchanger; at last, the liquid nitrogen is recycled and residual liquid is discharged. In the negative-pressure liquid nitrogen subcooler, defect that a constant-pressure liquid nitrogen subcooler only can provide the liquid nitrogen with the minimum temperature of 77 DEG C can be overcome, heat sink temperature can be further reduced, adjustable heat sink temperature between 70 DEG C and 77 DEG C can be achieved, equipment is simple, effect is good and cost is low.

Technology for bulk preserving spermatozoa of Chinese sturgeon through freezing at ultralow temperature comprises collecting and detecting fresh spermatozoa, diluting, balancing, adding antifreeze, subpackaging, program cooling, and preserving in liquid nitrogen container of -196deg.C. Each bulk can freeze 100 mL fresh spermatozoa. when the first bulk spermatozoa is in the procedure cooling step, after 5 minute, starting diluting the second bulk spermatozoa, and repeating above steps until all spermatozoa is preserved 8-12 h before its effective time. The diluent is Tris-HCl 20-30 millimole, sucrose 30-60 mol, potassium chloride 2-10 millimole, and distilled water 1000mL, and regulating pH to 8-8.5 with HCl. The antifreeze is methanol. The invention can efficiently carry out bulk preservation of Chinese sturgeon spermatozoa through freezing at ultralow temperature and long term ultralow temperature freezing preservation, and provide enough spermatozoa resource for artificial propagation of Chinese sturgeon.

The invention discloses a high temperature superconductive electromagnetic deironing element, which comprises the following parts: superconducting magnet, programmed power and magnetic control computer (1), wherein the screwed pipe coil axle of vertical and horizontal superconductive magnet (4, 5) is perpendicular with power supplied by two programmed energy (2, 3); the spatial working magnetic field is formed in the magnetic shaft plane; the liquid nitrogen container (12) lies between low-temperature container (17) and thermal radiation screen (16), which is assembled on the thermal radiation screen (16); the thermal radiation screen (16) is suspended in the low-temperature container (17); the nitrogen fixation container (15) is loaded in the thermal radiation screen (16); the disc-type windings (14) is assembled in the nitrogen fixation container (15); the serial port of computer (1) is controlled by magnetic field to connect serial ports of two programmed superconductive powers (2) and (3), which can adjust the powers (2) and (3) to control the direction and strength of working spatial magnetic field.