【Product name】Liquid nitrogen, also known as liquid nitrogen gas.

【Product overview】According to the Classification and Labelling of Hazardous Chemicals (GB13690-1992), liquid nitrogen is classified as Class II compressed gas and liquefied gas, and belongs to hazardous chemicals.

【Product characteristics】Colorless, odorless, and non-toxic gas. Low annual, non corrosive, non flammable, and extremely low temperature.

Boiling point -196.56 ℃, it absorbs a large amount of heat during vaporization, and contact may cause frostbite. Liquid nitrogen has strong expansibility, and 1 cubic meter of liquid nitrogen can expand to 696 cubic meters of pure gaseous nitrogen (21 ℃). In industry, liquid nitrogen is obtained through air fractionation, liquefied in a pressurized and cooled environment, and separated by utilizing the different boiling points of each component in the air.

The chemical properties of liquid nitrogen manifest as its inactivity, meaning it does not undergo chemical reactions with other substances. The chemical properties of liquid nitrogen also include its non toxicity and non flammability.

【Application area 】

Cryotherapy: particularly in the cryopreservation and transplantation applications of biological samples. The low-temperature characteristics of liquid nitrogen make it an effective cooling tool, especially when reactions and preservation of biological samples require extremely low temperatures. During the phase transition period from liquid to solid in biological samples, heat is released, leading to a temperature rise that may cause damage to cells. Therefore, it is crucial to accurately determine the phase transition point of biological samples and use microcomputers to develop cooling programs. By increasing the input of liquid nitrogen during phase transition, temperature rise can be overcome to ensure the safe passage of cells through the phase transition period, thereby improving the survival rate of frozen samples.

Preservation of living tissues: The low-temperature characteristics of liquid nitrogen make it an effective preservation method that can maintain the activity and structure of living tissues for a long time. In addition, liquid nitrogen is also used to store biological samples, sperm, and eggs, ensuring that they maintain their original biological activity for a long time.

Welding and metal processing: The freezing treatment capability of liquid nitrogen makes it easier for metals to shape during processing, such as freezing mold bending and extrusion. In addition, liquid nitrogen can also be used for grinding to improve the smoothness of metal surfaces. These applications all benefit from the low-temperature characteristics of liquid nitrogen, which can effectively change the physical state of metals and optimize the processing.

Transportation and storage: mainly used for storing and transporting biological samples, cells, tissues, sperm, etc., to ensure that these biological samples maintain their activity and integrity for a long time. In addition, liquid nitrogen can also be used to store semiconductor materials and other chemicals, providing a low-temperature environment for these materials to ensure their quality and stability.

Maintaining food quality: Due to the extremely short freezing time of liquid nitrogen, food can retain its original color, aroma, taste, and nutritional value to the maximum extent after liquid nitrogen treatment.

Beauty field: commonly used in cosmetic surgery to reduce bleeding, alleviate pain, and accelerate healing. Liquid nitrogen can also be used for skin treatment, such as cryotherapy, to remove blemishes or lesions on the surface of the skin. This method is commonly used to treat warts, moles, or other skin problems, accurately removing the affected area while reducing damage to surrounding tissues.

【Usage and precautions】

Appropriate labor protective equipment such as safety masks, goggles, and cold gloves must be worn to prevent skin frostbite.

In the room where liquid nitrogen is used and stored, good ventilation should be maintained to avoid oxygen deficiency and suffocation of personnel.

After one year of use, the liquid nitrogen tank should be cleaned and disinfected once. When cleaning, it is necessary to first wash with neutral detergent, then rinse with warm water not higher than 40 ℃, drain the water, and blow dry with a blower. After the inner container is fully dried, liquid nitrogen can be filled again.

【Packaging and storage】

The liquid nitrogen tank should be stored in a well ventilated and cool place, away from direct sunlight. The liquid nitrogen tank should not be tilted, placed horizontally, inverted, stacked, collided with each other or other objects. It should be handled gently and kept upright at all times, and the storage area should be equipped with emergency response equipment for leaks.