Effects of pressure on the structural, electronic and vibrational properties of solid carbon dioxide phases

The structural, electronic and vibrational properties of the solid carbon dioxide phases (Ⅰ, Ⅱ, Ⅲ, Ⅳ) at pressures of 0 to 70 GPa are studied by first-principles calculations. The calculated...

Concepts, History, Principles, and Application of Germplasm Cryopreservation Technology

Germplasm are living genetic resources that can serve as bearers of heredity, and include germ cells and their precursors, plant seeds and pollen, animal sperm, oocytes, embryos, and larvae. Cryopreservation refers to the preservation of biological materials at extremely low temperatures, typically using solid carbon dioxide at -80°C or liquid nitrogen at -196°C for freezing, and cryogenic storage in perpetuity. Germplasm cryopreservation is an important technology applied for medical treatment, maintenance of biological diversity, preservation of valuable genetic resources, assistance of breeding programs, and conservation of imperiled species. This extension publication is intended to introduce the basic concepts, history, principles, and applications of germplasm cryopreservation technology.

Charged Particle (Negative Ion)-Based Cloud Seeding and Rain Enhancement Trial Design and Implementation

China has been suffering from water shortage for a long time. Weather modification and rainfall enhancement via cloud seeding has been proved to be effective to alleviate the problem. Current cloud seeding methods mostly rely on solid carbon dioxide and chemicals such as silver iodide and hygroscopic salts, which may have negative impacts on the environment and are expensive to operate. Lab experiments have proved the efficiency of ion-based cloud seeding compared with traditional methods. Moreover, it is also more environmentally friendly and more economical to operate at a large scale. Thus, it is necessary to carry out a field experiment to further investigate the characteristics and feasibility of the method. This paper provides the design and implementation of the ion-based cloud seeding and rain enhancement trial currently running in Northwest China. It introduces the basic principle of the trial and the devices developed for it, as well as the installation of the bases and the evaluation method design for the trial.

Using low-temperature technologies to prevent emergency situations at sea and rivers during extraction, production and transportation of hydrocarbon raw materials

The paper highlights the chemically hazardous objects of marine and river infrastructure: offshore drilling platforms and oil production platforms; pipelines transporting liquid and gaseous hydrocarbon fuels along the sea bottom and above the ground; marine tankers transporting oil, fuel oil, gaseous and liquid ammonia; coastal terminals handling and shipping hydrocarbon raw materials, distillation products; gas producing plants and oil refineries; storage facilities for chemi-cally hazardous substances, etc. There are proposed new technologies for combating oil emissions during deep-water drilling, as well as for safe ways of transporting hydrocarbons through subsea pipelines and by oil tankers. These technologies are based on the methods of using low-temperature freons and cryogenic liquids. There are considered the methods of using machine cooling technologies, where the cascade refrigeration units work on various refrigerants, as well as using solid carbon dioxide and liquid nitrogen. Liquid nitrogen having a low boiling point (about minus 196C) has a higher rate of seawater freezing and forms stable ice layers on flat and cylindrical surfaces. There are given the examples of the experimental data to determine the growth rate of ice in the water frozen by liquid nitrogen. There has been given the chart of an underwater cryo-cuvette consisting of a metal panel with sockets, heat-insulated barrels, a tank for storing liquid nitrogen, a nozzle for filling the cryoagent, adjusting eyebolts, an object for freezing and transportation, and a safety valve. The underwater cryo-cuvette is designed to work with barrel-shaped objects. Envi-ronmental safety of transportation and production of natural hydrocarbon raw materials is signifi-cantly improved in the course of operation of the new technologies.