346 results about "Refrigerated temperature" patented technology

The invention provides a food storage early warning method and system based on artificial intelligence. The method comprises the following steps: acquiring an internal shot image of a target refrigerator, a multi-source sensing signal and the putting time of each food; performing image denoising and enhancement processing on the internal shot image to obtain a pre-processed image; performing image recognition according to the preprocessed image to obtain food information of each type of food; the food information comprises food types, food numbers and food colors; performing signal analysis on the multi-source sensing signal to obtain temperature information, humidity information and gas information; inputting the putting time, the temperature information, the humidity information, the gas information and the food information into a preset food freshness prediction model to obtain a prediction result; and performing early warning according to the prediction result. The food freshness can be intelligently monitored, early warning can be given out in time, and therefore food waste is effectively reduced, and the food management efficiency and safety are improved.

The utility model relates to a microenvironment fresh-keeping refrigerator, which relates to the field of electric appliances, and acquires temperature, humidity, oxygen, ozone, negative ion concentration, air pressure, air quality data and stored object data of a microenvironment fresh-keeping chamber through a data acquisition module. The regulation and control device is used for controlling the air charging and sucking pump, the water feeding and draining pump, the adsorption type air conditioning device, the humidifying device, the refrigerating device, the superoxide generator, the negative ion generator and the catalyst controlled release device according to the acquired data by combining internet big data and set data; various fresh-keeping elements such as air components, airflow pressure, temperature and humidity, oxygen, ozone and negative ion concentration and air sterility and cleanliness in the refrigerator are regulated and controlled in an omnibearing and multi-angle digital targeted mode, harmful residues on the surfaces of fruits and vegetables are degraded, harmless and dead-corner-free sterilization and disinfection are conducted, rotten elements and freshness loss factors are removed at fixed points, corrosion prevention and fresh-keeping elements are precisely maintained, and the fresh-keeping effect is good. Nutrient components of fruits, vegetables, meat, fish and stored products and freshness of original shapes and original tastes are cared rapidly and permanently, and a fresh-keeping refrigerator microenvironment with precise fresh keeping and comprehensive nutrition keeping is created.

The invention discloses an efficient and lasting multifunctional refrigerator deodorant which comprises the following components: (a) 50-85wt% of a porous adsorption material with a high specific surface area; (b) 5-30 wt% of a catalyst capable of effectively catalyzing and decomposing organic odor molecules in a low-temperature environment of 0-10 DEG C; and (c) 3 to 15 weight percent of long-acting slow-release type broad-spectrum antibacterial agent. According to the efficient and lasting refrigerator deodorant and the preparation method thereof, the dual effects of physical adsorption and low-temperature catalytic decomposition are utilized, multiple types of peculiar smell molecules can be rapidly adsorbed and thoroughly decomposed, and the deodorization efficiency is remarkably higher than that of a single adsorbent; the service life is greatly prolonged and is 3-5 times that of common activated carbon, the food decay speed is reduced, the food fresh-keeping period is indirectly prolonged, and food safety is guaranteed. The use process is safe and reliable, the use is convenient, external conditions such as illumination and heating are not needed, the device can be directly placed in a refrigerator, the replacement frequency is reduced due to long-term effect, and the comprehensive use cost is low.

The invention relates to a control method of refrigeration equipment, the refrigeration equipment and a refrigerator and relates to the technical field of refrigeration, and the method comprises the steps that under the condition that the temperature of an object in the refrigeration equipment is smaller than a preset temperature, the cooling speed change rate of the object is determined; under the condition that the cooling speed change rate is smaller than a preset value, the freezing temperature of the article is obtained according to the target cooling speed of the article; and the refrigeration temperature in the refrigeration equipment is adjusted to be higher than the freezing temperature. By means of the control method of the refrigeration equipment, the refrigeration equipment and the refrigerator, the freezing temperatures of different objects can be obtained, the refrigeration temperature is adjusted to be higher than the freezing temperature, and the object freezing probability is reduced.

The invention discloses a method for efficiently depolymerizing waste PET polyester at low temperature, which comprises the following steps of: dissolving a cleaned and dried PET material with a good solvent, and distilling to recover the solvent after the PET material is completely dissolved, so as to obtain a PET sample; mixing the treated PET sample with a catalyst, ethylene glycol and a cosolvent, putting the mixture into a pressure-resistant reaction tube, stirring and reacting for a certain time at a specific temperature, and then ending the reaction; carrying out reduced pressure distillation on the reaction liquid to recover the cosolvent; stirring the residual solution in hot water for a certain time, performing hot filtration, washing and drying filter residues with hot water, refrigerating filtrate in a refrigerator, filtering, collecting solids, and drying to obtain the product. The method has the advantages of simplicity in operation, low reaction temperature, high reaction rate, no metal ions and the like, and can realize green and efficient recovery of waste polyester; the method can be applied to the fields of polyester fibers, bottle flakes, films and the like, and has relatively high industrial feasibility and application prospects.

The present invention provides a food ripening control method and a refrigerator, the food ripening control method comprising: controlling an electric damper to open, controlling a humidifying device to start, controlling a variable frequency fan to start, obtaining an initial weight of the food to be ripened and a first weight after a first preset time, and calculating a weight change rate; comparing the weight change rate with a preset weight change rate, and adjusting a humidity value and a wind speed in a ripening chamber according to the comparison result; obtaining a second weight of the food to be ripened at a second preset time interval, and calculating a water evaporation rate according to the second weight and the initial weight; and adjusting the humidity value and wind speed in the ripening chamber according to the evaporation rate using a preset module adapted to the evaporation rate; judging the thickness of the food by obtaining the weight change rate within a preset time, and then adjusting the wind speed and humidity, and adjusting the wind speed and humidity at different ripening stages of the food to solve the problem that adjusting the wind speed according to the water evaporation rate easily causes the food to dry too fast or too slow, thereby affecting the taste of the food.

A tag includes: a temperature indicating material; and an identifier that presents identification information uniquely identifiable by appearance. A control method includes: capturing, with a camera, an image of a first food item that is a food item to be stored, or a food item stored, in an interior of a refrigerator to generate the image showing the tag, the tag being attached to the first food item; obtaining a temperature of the first food item by analyzing a color of the temperature indicating material included in the tag shown in the image generated; and generating control information to control cooling of the interior of the refrigerator by comparing the temperature obtained with an appropriate temperature range for the interior of the refrigerator, and transmitting the control information generated to the refrigerator.

The invention discloses a seasoning storage control method, system and device, a refrigerator and a storage medium, and the method comprises the steps that seasoning in seasoning areas in the refrigerator and position information of the seasoning are obtained, and the seasoning areas comprise a normal-temperature seasoning area and a cold storage seasoning area; controlling the normal-temperature seasoning area and the refrigeration seasoning area to work based on the preset temperature and the preset humidity; in the storage process of the seasonings, state information of the seasonings is obtained; and working parameters of temperature and humidity elements in the normal-temperature seasoning area or the cold storage seasoning area corresponding to the seasonings are adjusted according to the state information and the position information of the seasonings, so that the areas where the seasonings are located in the seasoning areas have temperature optimization values and humidity optimization values. According to the seasoning storage control method, system and equipment, the refrigerator and the storage medium, the problem that the freshness of seasoning in an existing refrigerator is reduced due to the fact that the seasoning is prone to being affected by the environment is solved, the freshness of the seasoning is effectively guaranteed, and the service life of the seasoning is prolonged.

To provide an electric turbomachine for a freezer that comprises a heat insulating mechanism for suppressing heat input from a motor to a refrigerant flowing in a refrigerant flow path of a turbine, and has a high degree of freedom in designing a structure for fixing a stationary vane.SOLUTION: An electric turbomachine for a freezer comprises a motor and a turbine connected to the motor via a rotational shaft. The turbine includes a stationary vane provided upstream of a turbine wheel in a refrigerant flow path. A casing includes a partition part configured to partition the motor and the refrigerant flow path of the turbine. The partition part is provided with a heat insulating mechanism, and the stationary vane is fixed to a shroud-side flow path wall part.SELECTED DRAWING: Figure 2

The invention discloses constant-temperature curing and loading integrated test equipment for preparation of mixing piles, and relates to the technical field of preparation of mixing piles, and the constant-temperature curing and loading integrated test equipment comprises a refrigerator, a constant-temperature device, a loading device and a multi-angle mixing pile preparation device. According to the constant-temperature curing and loading integrated test equipment for preparing the stirring pile, through coordination of heating and refrigerating, the temperature control precision of a conventional refrigerator is improved, and the uniformity of a temperature field in the refrigerator is guaranteed; the whole process from pile manufacturing, maintenance to loading is completed in the same constant-temperature space, interference caused by process conversion is eliminated, finally, the reinforcing process and effect of the inclined cement-soil mixing pile in the high-temperature frozen soil roadbed are accurately simulated, and test errors caused by temperature fluctuation and process separation in a traditional method are avoided; by quickly adjusting the angle of the stirring rod and selecting different spray hole combinations, one device can simulate various construction processes, different scientific research and test requirements are met, and the flexibility in use is improved.

The invention provides a refrigerator valve fault detection method and system, and the method comprises the steps: obtaining operation data which is data stored according to a time sequence, determining a frosting period according to the operation data, extracting the data of the frosting period from the operation data, and detecting the data of a detection unit; the detection unit is a detection unit in a frosting period; calculating a data occupancy rate when the refrigerating chamber temperature data of the detection unit is greater than the preset refrigerating temperature and a data occupancy rate when the freezing chamber temperature data of the detection unit is less than the preset freezing temperature, so as to confirm a first fault direction through the data occupancy rate of the preset refrigerating temperature, and confirm a second fault direction through the data occupancy rate of the preset freezing temperature, the first fault direction is from the electric valve to the refrigeration direction, and the second fault direction is from the electric valve to the freezing direction. According to the method, whether the refrigerator valve breaks down or not is judged by obtaining the operation information of the refrigerator, the fault can be found in time, the maintenance period of the refrigerator is shortened, and the maintenance efficiency is improved.

To obtain a ventilation air conditioning system which can prevent reduction of the volume of ventilating air caused by freezing in a heat exchanger and enables reduction of a heating load.SOLUTION: A ventilation air conditioning system 100 includes: an air conditioner 1 having an outdoor unit 12 which heats a refrigerant, and an indoor unit 11 including a first condenser 21 which heats air to be sent to an indoor space by the refrigerant; a ventilation device 3 having a heat exchanger 31 which conducts heat exchange between air to be supplied from an outdoor space to an indoor space and air discharged from the indoor space to the outdoor space, the ventilation device 3 configured to supply air to the indoor space and exhaust air from the indoor space; a second condenser 22 which heats air taken from the outdoor space thereinto with the refrigerant before the air is introduced into the heat exchanger 31; and a refrigerant circulation circuit part 20 forming a passage of the refrigerant which is transported from the outdoor unit 12 to each of the first condenser 21 and the second condenser 22 and returned to the outdoor unit 12.SELECTED DRAWING: Figure 1

The invention provides a fermentation device, a refrigerator and a fermentation control method.The fermentation device comprises a PH testing module, a lactic acid content testing module, a temperature control module and a control module, the temperature control module can be controlled to keep the temperature value k0 in a liquid storage device at a preset temperature value K1, and a joint error value is calculated according to the PH value and the lactic acid content value of liquid in the liquid storage device; and determining whether fermentation is completed according to the range of the joint error value. The temperature in the liquid storage device of the fermentation chamber is adjusted in real time, a good temperature condition is provided for fermentation, the PH value and the lactic acid content value n of the liquid in the liquid storage device in the fermentation process are monitored, meanwhile, the joint error is calculated, the lactic acid content and the PH value of the fermentation liquid and the viable count in the fermentation liquid are effectively controlled, the taste of the fermentation liquid is guaranteed, and the fermentation time is shortened. And the nutritional value of the fermentation liquid is ensured.

The invention relates to the field of advanced flame-retardant aerogel materials, in particular to a flame-retardant heat-insulating nano-cellulose composite aerogel material, a preparation method and application. The preparation method comprises the following steps: S1, dispersing inorganic nanosheets, a nanocellulose solution and sodium alginate in water, and stirring to obtain a mixed solution; the mass ratio of the inorganic nanosheets to the nanocellulose solution to the sodium alginate to the deionized water is (0-5): (50-100): 2: 98; s2, slowly pouring the mixed solution into a mold, putting the mold into a refrigerator for freezing, after a sample is completely frozen, putting the sample into a surface active solvent, and adding metal chloride and a cellulose cross-linking agent into the solvent at the same time; then sodium alginate ion crosslinking and cellulose crosslinking are carried out under the condition of subzero; the mass ratio of the metal chloride to the cellulose cross-linking agent to the surface active solvent is (0.5-1.1): (1-2): 200; and then putting the mixture into a blast oven for normal-temperature and normal-pressure drying to obtain the flame-retardant and heat-insulating nano-cellulose composite aerogel material.

The invention relates to the technical field of biological preservation, in particular to a refrigerator food material preservation method and system based on a multi-modal decision dynamic weight mechanism, and the method comprises the steps: collecting multi-modal characteristic data of food materials; constructing a dynamic weight attention mechanism, and dynamically adjusting the fusion weight of each modal feature; combining a GNN graph neural network to construct a food material spoilage correlation graph, and outputting a spoilage risk prediction value at a t moment; an optimal fresh-keeping strategy combination is generated through multi-objective optimization; and processing real-time disturbance by adopting a model predictive control method and outputting a cooperative control signal. According to the method, the dynamic weight attention mechanism based on the food material category and the storage state is constructed to realize adaptive weight fusion of temperature, humidity, gas, weight and vision sensor modalities, so that the time sequence adaptability, the category specificity and the response sensitivity of multi-modal fusion are improved; and the contribution degree of the key sensor can be adaptively enhanced by the system in different scenes, and the corruption risk prediction precision is remarkably improved.

The invention discloses an ABS (Acrylonitrile Butadiene Styrene) composite material and belongs to the technical field of composite material preparation. The ABS composite material comprises ABS, a flame-retardant noise-reducing filler and a silane coupling agent, the flame-retardant and noise-reducing filler is salix mongolica fiber loaded with UiO-66; the flame-retardant and noise-reducing filler is prepared by the following steps: weighing salix psammophila fibers, ZrCl and terephthalic acid, adding the materials into dimethylformamide, performing ultrasonic treatment to uniformly disperse the materials, then stirring and refluxing for a certain time in a nitrogen atmosphere at a certain temperature, washing to remove unreacted ligands and metal ions, and drying for a certain time to obtain the flame-retardant and noise-reducing filler. The invention is applied to the aspects of flame retardance and noise reduction of refrigerators, solves the problem that the existing salix psammophila fiber cannot be used as a flame-retardant and noise-reduction material for refrigerators due to the flammable characteristic, and has good flame-retardant and noise-reduction performance.

The invention discloses a method for extracting plukenetia volubilis linneo oil based on pulsed electric field and freeze thawing synergistic demulsification. The method comprises the following steps: shelling plukenetia volubilis linneo, crushing the plukenetia volubilis linneo into powder, stirring the powder with deionized water to form a uniform solution, adjusting the pH value to 9.5-11.5, adding alkaline protease, carrying out water bath enzymolysis, standing to room temperature, separating, taking an upper-layer plukenetia volubilis linneo emulsion, carrying out pulsed electric field treatment, freezing and thawing, and centrifuging to obtain yellow and transparent plukenetia volubilis linneo oil. The method comprises the following steps: treating a plukenetia volubilis linneo emulsion formed in an aqueous enzymatic method system in a pulsed electric field static treatment chamber, controlling the electric field intensity at 3.5-8.5 kV / cm, immediately transferring the emulsion treated by the electric field into a refrigerator at-20 DEG C, freezing for 4-8 hours, unfreezing at room temperature, and centrifuging to obtain upper grease. The obtained sacha inchi oil is high in yield and good in nutritional quality, and has the advantages of being short in demulsification period, efficient in oil-water separation and the like.

The invention provides a defrosting control method and device for judging full frost of a fin evaporator of a refrigerator. The defrosting control method comprises the steps that the environment temperature, the average temperature of an air return pipe, the door opening and closing frequency and the accumulated operation time of a compressor are collected to generate an initial frost control strategy; according to the environment temperature, the air return temperature and the refrigeration starting point temperature when the refrigerator is loaded are obtained; calculating a return air temperature difference value according to the return air pipe average temperature and the return air temperature; if the air return temperature difference value is larger than or equal to the first preset temperature value, an initial frost control strategy is executed; if the air return temperature difference value is smaller than the first preset temperature value and larger than or equal to the second preset temperature value, a first defrosting control strategy is executed; and if the return air temperature difference value is smaller than a second preset temperature value, the refrigeration sensor temperature is collected in real time through a refrigeration sensor temperature collection module to calculate a refrigeration temperature difference value, whether a second defrosting control strategy is executed or not is judged according to the refrigeration temperature difference value, and the problem that it is judged that the refrigerator fin evaporator is full of frost inaccurately is solved.

Provided is an automated analyzer comprising a reagent cooler such that it is possible to cool the entire interior of the reagent cooler with one refrigeration device while also preventing condensation in the reagent cooler.　This automated analyzer comprises: a reagent cooler that cools a plurality of reagent containers; a heat pipe that is provided inside the reagent cooler and cools the interior of the reagent cooler; a cooling device that cools the heat pipe; a dehumidification pipe that conveys air from the exterior of the reagent cooler and discharges the same from an end thereof into the reagent cooler interior, at least one section of said dehumidification pipe being in contact with or in the vicinity of the heat pipe; and a first drain that drains, to the exterior of the reagent cooler, condensation water which drains from the end of the dehumidification pipe.

The utility model discloses an insect catching device which comprises the following components: a box body which is internally provided with a dormancy area which is used for collecting insects and a freezing area which can cool and freeze the space in the dormancy area; the catching mechanism is connected to the dormancy area and used for catching external insects into the dormancy area; and the screening table is detachably connected to the box body and used for placing the captured insects for screening testing. Insects are directly caught into the dormancy area through the catching mechanism, then the insects in the dormancy area are quickly frozen and dormant through the freezing area, and finally the insects are transferred to the screening table to be screened and tested, so that the working efficiency of operators is greatly improved. Tap water is directly put into the freezing area, the freezing area is naturally frozen in a refrigerator and then can be used, the method is simple and convenient, the physical freezing technology is utilized in the catching process to enable the test insects to sleep quickly, the influence of drugs on the test insects is reduced, and the activity of the test insects in the testing process and the data reliability are improved.

The application provides a refrigerator control method and a refrigerator. The refrigerator comprises a cabinet, a storage space and a freezing space arranged below the storage space are defined in the cabinet, a compressor and a fan are arranged in the freezing space, the compressor is used for refrigeration, and the fan is used for refrigeration for the storage space in cooperation with the compressor. The control method comprises the following steps: acquiring an ambient temperature and a stop time of the compressor; acquiring a corresponding time threshold according to an interval in which the ambient temperature is located; if the stop time of the compressor is greater than the time threshold, the compressor and the fan are started; if a current temperature of the storage space is less than a temperature threshold, the fan is controlled to stop; and the compressor is controlled to stop after a preset time. According to the ambient temperature and the stop time of the compressor, the application controls the start and stop of the compressor and the fan, so that the freezing space also reaches a target temperature at a lower ambient temperature.

The application relates to a cold quantity distribution method and device, a refrigeration equipment and a computer readable medium. The method comprises the following steps: calculating the current refrigeration demand and freezing demand of the refrigeration equipment; determining a target cold quantity distribution strategy according to the refrigeration demand and the freezing demand; controlling the operation states of the refrigeration circuit and the freezing circuit respectively according to the target cold quantity distribution strategy, and controlling the on-off of the bypass pipeline according to the target cold quantity distribution strategy, so that the refrigeration evaporator in the refrigeration circuit is reused as an auxiliary condenser of the freezing circuit through the bypass pipeline, or the cold quantity of the freezing circuit is supplemented to the refrigeration circuit through the bypass pipeline, so that the cold quantity is distributed according to the actual demand of the refrigeration equipment. The application controls the operation states of the refrigeration circuit and the freezing circuit, and adjusts the on-off of the bypass pipeline between the two, so as to schedule the cross-circuit cold quantity, realize on-demand distribution of the cold quantity, and solve the technical problem that the cold quantity distribution of the existing refrigerator cannot adapt to the real-time demand of each temperature zone.

The invention provides a refrigeration equipment control method and device, a refrigerator and a computer readable storage medium. The method comprises the steps that a target freshness index of target food in a food storage bin is obtained; determining the index change speed of the target freshness index according to the target freshness index; and if the index change speed is greater than or equal to a preset speed change threshold value, adjusting operation parameters of the antibacterial equipment so as to reduce the decay speed of the target food. According to the refrigeration equipment control method, the target freshness index of the stored target food can be obtained firstly, and the index change speed of the freshness of the target food is determined according to the freshness index, so that the decay speed of the target food is determined. And if the decay speed of the target food is high, the operation parameters of the antibacterial equipment arranged in the refrigeration equipment can be adjusted, then the activity of microorganisms in the refrigerator is reduced, the decay speed of the food is reduced, and compared with pure temperature and humidity preservation, the food preservation effect is improved.

This application provides a refrigerator. The refrigerator includes a housing provided with at least one magnetic field preservation chamber, a magnetic field generating device for generating a magnetic field within the storage space of the magnetic field preservation chamber, and a cooling system for cooling the magnetic field preservation chamber. The magnetic field generating device is configured to set the magnetic field strength inside the storage space in the range of 10 gauss to 100 gauss, and the cooling system is configured to set the temperature inside the storage space in the range of -10°C to 0°C, or the magnetic field generating device is configured to set the magnetic field strength inside the storage space in the range of 5 gauss to 40 gauss, and the cooling system is configured to set the temperature inside the storage space in the range of -30°C to -15°C. This makes it possible to refrigerate food at sub-zero temperatures, or to reduce the formation of large ice crystals inside when freezing food, thereby improving preservation effectiveness.

A process using a liquid heat transfer fluid with a triple point temperature below -125°C, such as isopentane, to recover the cold energy from the sublimation and melting of frozen substances on heat exchanger surfaces, particularly CO2. The same heat transfer fluid circulates in two coupled circuits: one acting purely as a heat transfer fluid, the other as a heat transfer fluid during defrosting, and to transfer the cooling capacity recovered during defrosting. Figure 1

To provide a gas dosing unit capable of operating a cryoinstrument after starting with desired cooling power without delay even when the temperature of a gas storage is low.SOLUTION: A gas dosing unit 10 is configured to adjust a desired gas flow and includes a pressure control module having a pressure reduction device. In a case of a normal room temperature, a control device controls the pressure reduction device for adjusting a desired pressure or a desired gas stream. If the room temperature and / or the temperature of the connected gas storage 12 is lower and accordingly, the gas pressure applied at an inlet connection 15 of the gas dosing unit is insufficient for the correct operation of the pressure control module, the control device activates a compressor arranged in a gas path, which increases the pressure upstream of the pressure control module to a value appropriate for the correct operation of the pressure control module. In doing so, a cryoinstrument 11 can be correctly activated and used independent of the room temperature and the pressure inside the pressure storage.SELECTED DRAWING: Figure 1

A complex ester of a divalent carboxylic acid, a divalent alcohol, and at least one selected from a monohydric alcohol and a monocarboxylic acid, wherein the divalent alcohol consists of a branched divalent alcohol having no quaternary carbon.

The invention provides a de-muttony cooked mutton and a de-muttony treatment process, the de-muttony treatment process of the cooked mutton comprises mutton pretreatment, soaking and rinsing treatment, boiling treatment and freezing and unfreezing treatment, and the cooked mutton blocks rinsed by soaking liquid and boiled by boiling liquid have the advantages that the mutton blocks can be frozen and unfrozen; a treatment mode of combining an ultra-fast freezing mode and a 4 DEG C refrigerator slow unfreezing mode is selected, so that the mutton smell of the cured mutton is reduced to the maximum extent. Meanwhile, the optimal de-odoring process of the cured mutton is determined by research as follows: the pH value of a soaking solution is 8.79, the pH value of a cooking solution is 8.49, and the soaking time is 7.8 hours. The concentrations of five key mutton smell substances before and after freezing and thawing of the cooked mutton prepared by the optimal mutton smell removal process are reduced compared with those of the original process, the mutton smell and fat taste are both lower than those of the original process, the meat flavor and nut taste are also remarkably improved, and the overall flavor of the cooked mutton is improved.

The invention discloses a preparation method and application of a lithium iron phosphate composite material, and relates to the technical field of preparation of lithium iron phosphate composites.The preparation method comprises the following steps that 1, lithium iron phosphate, carbon nanotubes and bacterial cellulose are mixed according to the mass ratio of (7-9): (0.5-1.5): (0.5-1.5), and then the mixture is placed in a mold; (2) horizontally placing the mold containing the sample in a freezing refrigerator, and freezing at-60 DEG C to-50 DEG C for 12-24 hours to ensure that the mold is completely frozen and crystallized; and (3) taking out the sample which is completely frozen and crystallized, putting the sample into a vacuum freeze dryer, and carrying out drying treatment for 24-48 hours at the temperature of 60 DEG C below zero to 50 DEG C below zero to obtain the novel lithium iron phosphate composite material. The lithium iron phosphate composite material prepared by the invention has excellent ionic conductivity, can be applied to lithium extraction of salt lake brine, and has excellent lithium extraction performance.

The invention relates to a hydrogen liquefaction plant comprising a hydrogen supply circuit (3) to be cooled, a plurality of heat exchangers (4, 5, 6, 7, 17) arranged in heat exchange with the supply circuit (3), a first pre-cooling device (8), a second pre-cooling device (9) and a cooling system (10) in heat exchange with the set (4, 5) of exchangers, to lower the temperature of the hydrogen to a temperature below the critical temperature of hydrogen, the first pre-cooling device (8) comprising a closed-cycle refrigerator of a first cycle gas comprising at least three components, a first centrifugal compressor (18), a cooling unit (180), three phase separators (28, 48, 88) configured to separate the two-phase fluid,the refrigeration cycle refrigerator of the first pre-cooling device (8) comprising a first expansion element (78) configured to expand the liquid produced by one of the phase separators (48) and return this fluid to a first centrifugal compressor (18) via a passage through a heat exchanger of the exchanger assembly. Abbreviated figure: Fig. 1,