Welcome to Cryo: A New Open-Access Journal

Cryogenics is an important branch of physics, representing a foundational field in modern science. Cryogenic technology provides core support for superconductor applications, rocket launches, space exploration, quantum science, and many other topics. Cryogenic technology and equipment are developing rapidly and progressing high-tech facilities. Due to the importance and influence of this field, we are here to build the new journal, Cryo (ISSN: 3042-4860) [1], which will serve numerous researchers and technicians working in cryogenics and provide a public platform to exhibit their new ideas and results.

Generally, low temperature refers to a temperature range below 120 K. According to the technical fields involved, the temperature zones are mainly divided by refrigeration working fluids, followed by natural gas liquefaction, air liquefaction and separation, hydrogen liquefaction, helium liquefaction, and the superfluid helium temperature zone. Lower temperatures are classified by refrigeration methods for extremely low temperature refrigeration below 1 K, such as adsorption refrigeration, adiabatic demagnetization refrigeration, helium three compression refrigeration, dilution refrigeration, etc. Since 1877, researchers have been attempting to obtain different refrigeration temperatures and provide the required refrigeration capacities. In recent decades, the demand for cryogenic technology has increased, leading to the rapid development of related technologies and equipment. The application scale of liquefied natural gas, liquid oxygen, liquid nitrogen, liquid hydrogen, liquid helium, and even superfluid helium continues to set new records, leading to an unprecedented growth in the application of cryogenic technology.

The investment and construction scale of large-scale scientific devices such as electron colliders, particle accelerators, high-power ray facilities, high-gain cold neutron sources, and strong magnetic fields have driven the progress of helium refrigeration technology, and large-scale superfluid helium refrigeration (2 K) has exceeded the kilowatt level. The technical challenges brought by ultra-low temperature and large flow rates have been continuously overcome under the traction of demand.

Hydrogen energy is a much desired clean energy source, referred to as the ultimate energy source. Hydrogen, as a substance, is also capable of energy storage and on-demand conversion. Liquid hydrogen is one of the best ways to utilize hydrogen energy in the process of hydrogen energy storage and transportation, but the process of hydrogen liquefaction, storage, transportation, and utilization involves a numerous cryogenic technologies and cryogenic liquid hydrogen equipment. From saturated liquid hydrogen (20 K) to supercooled liquid hydrogen, and even the development and application of slurry hydrogen (13.8 K), scientists and technicians are committed to the development of advanced, efficient, and reliable technologies and equipment to serve the growing needs of the liquid hydrogen industry.

Large-scale liquid rockets use a combination of liquid oxygen/liquid hydrogen, liquid oxygen/liquid methane, or liquid oxygen/kerosene as power fuel. Liquid rockets and ground filling systems need to consider the entire process of cryogenic technology. Although some countries, such as the United States and Russia, have accumulated a wealth of experience in cryogenic rocket design and application, in today’s continuous progress in science and technology, there are still many difficulties in aerospace cryogenic technology. The frequent failures in rocket launches and flights indicate that cryogenic technology still has a long way to go in the application of cryogenic liquid rockets. In the future, cryogenic technology regarding reuse, long-term orbit, space refueling, and multiple start-ups of rockets will be an important core problem.

Space exploration is the most notable way for human beings to explore the universe, and deep space is a cold and dark space environment with a high vacuum and an ultra-low temperature. From Earth-orbiting satellites to deep space probes, refrigeration carried out by cryocoolers has a cooling temperature ranging from 100 K to mK and a cooling capacity ranging from 100 W to mW, or even micro-watts. With the development of large-scale space technology, such as manned lunar landings, building a lunar station, and manned landings on Mars, the demand for large-scale cryogenic refrigeration is an important technology.

The development of quantum science has led to the progress of ultra-low temperature refrigeration technology, and the emergence of quantum effects needs to be realized under the conditions of mK temperatures. To carry out physical research in quantum computing and quantum communication, the support of cryogenic refrigerators is needed. Cryogenic engineering requires the research and development of refrigerators with a base-level refrigeration temperature of 50 mK or lower. Meanwhile, the preparation of He3 working fluid is also extremely important in the research and development of refrigerators.

There are many applications of cryogenic technology that are not listed here. Cryogenic technology is used in various high-tech fields, and with the progress of science and technology, its application is more extensive and deeper than ever, and its scale will become larger. At present, cryogenic technology and research results are usually published in professional journals in application fields, or in general fluid mechanics, heat and mass transfer, or professional equipment journals. There is a lack of journals dedicated to cryogenic technology, which greatly restricts the mutual communication between cryogenic science and technology workers, which affects the effective transmission of relevant information.

The Cryo journal aims to provide an effective platform for cryogenic technology scientists and technicians to communicate and to make it easier for researchers to publish their research results. Authors submit their manuscripts through the platform, and after an initial screening, to peer review. As for the official acceptance time, the total period is as short as two months, which is very good news for scientific researchers. The journal accepts all kinds of research results related to cryogenic technology, including the research and development achievements of new refrigeration methods, cryogenic working fluids, unit equipment, and technological processes, and also welcomes the application achievements and reports of cryogenic technology. The purpose is to promote the exchange and interaction of cryogenic science ideas and the progress and development of cryogenic technology. No matter whether it is theoretical research, experimental results, a literature review, you are welcome to submit your works. The Editorial Office is available to authors for assistance and high-quality services.

I am pleased to be the Editor-in-Chief of Cryo in its first term. Because of my deep passion for cryogenics, I believe this is a great opportunity to serve my fellow scientists and promote technological progress. In my career of more than 40 years of research, I have conducted research on cryogenic technology across multiple temperature zones. Since the 1980s, I have been researching air separation technology and developing high-performance multi-stream cryogenic heat exchangers. In the early 1990s, I was engaged in research on superfluid helium heat exchange and completed my doctoral dissertation. Subsequently, I began research on natural gas liquefaction and LNG cold energy recovery and utilization. At the beginning of this century, I undertook the research and development of large-scale, low-temperature cold neutron sources, involving large-scale helium Brayton refrigeration and hydrogen liquefaction cycle technology. Later, I carried out research on aerospace cryogenic propellants, mainly involving the storage and filling of liquid oxygen and liquid hydrogen, as well as space thermal management. I have a comprehensive understanding of the technology and its application in the field of cryogenics; however, I still have a lot of expectations for new cryogenic technology. Relying on the platform of Cryo, I hope that the numerous researchers and technicians working in cryogenic fields will work together to help build this new communication channel and contribute to Cryo as an outstanding journal.