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Recent developments in vacuum freeze-drying technology at home and abroad. Vacuum freeze-drying technology is widely used in fields such as bioengineering, the pharmaceutical industry, the food industry, materials science, and the deep processing of agricultural and sideline products. Therefore, both domestically and internationally, considerable attention is paid to this technology. This can be seen just from domestic and international academic conferences. In China, the Chemical Engineering Professional Committee of the Chinese Chemical Society holds a national academic conference on drying technology every two years, at which numerous papers on freeze-drying technology are presented ； The Sixth Professional Committee of the Chinese Refrigeration Society holds a national academic conference on vacuum freeze-drying every four years, and all the papers presented at these conferences are related to freeze-drying ； At relevant conferences organized by the Agricultural Machinery Society, Food Science Society, Medicine Society, and Biology Society of the Chinese Vacuum Society, articles on freeze-drying are published. The International Society of Drying holds an academic conference every two years. At the IDS’98 conference, Professor A. Liapis from Missouri-Rolla University in the United States received the “Outstanding Freeze-Drying Award” for his significant contributions to basic research in vacuum freeze-drying ； The 2000 International Drying Conference saw the participation of over 30** and local organizations; 301 papers were presented, and 5 awards were given, the third of which was the “Outstanding Contribution to Freeze-Drying Award”” ； The 13th International Symposium on Drying was held in Beijing, China, in 2002. The proceedings consisted of 3 volumes, with articles on freeze-drying collected in Volume A. Among the 8 keynote speeches given at the conference, the achievements made by Northeastern University in maintaining the viability of corneas through freeze-drying were mentioned twice, and Japanese scholars offered to exchange visits to laboratories. 1. Research progress on the fundamentals of freeze-drying technology at home and abroad: Doctoral students at Tohoku University have successively developed heat transfer models for the freezing of materials on shelves, as well as heat transfer models for the freezing of corneas in cryostats. Sandall and King, among others, proposed a heat and mass transfer model for the sublimation drying process, commonly known as the URIF model (The Uniformly Retreating Ice Model). On this basis, Liapis and Lifchfield, among others, developed a desorption-sublimation model for the vacuum freeze-drying process. Current research hotspots include heat and mass transfer in biological cells during freeze-drying, as well as the theory of heat and mass transfer at the nanoscale. 2. Research trends in freeze-drying equipment at home and abroad. Freeze-drying equipment in China has been modernized. Domestically produced freeze-drying equipment for the pharmaceutical industry features comprehensive functionality, reliable operation, stable performance, and advanced control systems. It fully complies with GMP standards, and all its technical specifications meet the requirements for the freeze-drying of biological products and drugs. The main functions include hydraulic plugging inside the box ； Online Cleaning (CIP) ； Steam sterilization (SIP) ； Control of the main process parameters during freeze-drying, etc. Freeze-drying equipment for food processing has become larger in scale; the largest current freeze-drying units have a drying area of up to 200 m2. Tunnel-type semi-continuous freeze-drying equipment has also been developed and is operating well. Food freeze-dryers can all be automatically controlled by industrial computers, ensuring product quality. Abroad, there are more varieties and specifications of freeze-drying equipment than in China; the supporting equipment is complete, the energy-saving designs are more sophisticated, and continuous-type freeze-drying equipment can handle large production volumes. To ensure the quality of freeze-dried products and save energy, combined freeze-drying equipment that integrates freeze-drying devices with other drying devices is often used, such as spray freeze-drying equipment. 3. Research trends in freeze-drying processes at home and abroad. The freeze-drying processes for biological products and pharmaceuticals are quite complex; particularly, information regarding freeze-drying protectants and excipients is kept confidential by different countries and organizations. The content published in articles consists only of common, basic formulations. The main difference between domestic and international research efforts lies in the testing instruments. In China, it relies mostly on experiments and experience ； Foreign instruments are more advanced; devices such as cryobiological microscopes and scanning electron microscopes are widely used there, enabling higher speeds and greater precision in research. 4. Development trends in the application fields of freeze-drying technology at home and abroad. The use of freeze-drying technology in China’s food industry is developing rapidly, with most freeze-dried products being supplied as raw materials for the international market ； The application of freeze-drying technology in the fields of biological products and pharmaceuticals is advancing steadily. To enhance the efficacy of live bacterial and viral vaccines, as well as to improve the quality of drugs and their solubility, freeze-drying must be employed ； Applications in other fields are developing more slowly. Foreign researchers have a more open mindset, and they make extensive use of freeze-drying technology in the production of nanomaterials ； Lyophilization technology is applied in fields such as the restoration of ancient paintings and calligraphy, and the preparation of animal and plant specimens.