Molecular Dynamic Simulation Study on Replacement of Methane Hydrates with Carbon Dioxide Under Different Temperatures, Pressures, and Concentrations of Ethylene Glycol.

In order to alleviate the world energy resources crisis, the research and development of natural gas hydrates has a very important economic value and strategic significance. The CH4-CO2 replacement method can not only achieve geological storage of carbon dioxide but also more effectively mine natural gas hydrates. Based on molecular dynamics theory and the properties of natural gas hydrates, this paper delves into the replacement of methane hydrate with carbon dioxide under different temperatures, pressures, and concentrations of ethylene glycol (EG). We established a CO2-Hydrate model and three CO2/EG-Hydrate models with different concentrations of EG, and we simulated the radial distribution function (RDF), mean square displacement (MSD), and relative density distribution of each particle in the system in different conditions. The higher the temperature, the more unstable the methane hydrates are, and the methane hydrates are more prone to decomposition. Compared with 280 and 290 K, the temperature of 270 K is more favorable for carbon dioxide molecules to enter the hydrate layer and form carbon dioxide hydrates. The changes in pressure have little impact on the decomposition of methane hydrates, the rupture of water cages of methane hydrates, and the number of carbon dioxide molecules entering the hydrate layer under temperatures of 280 K and pressures of 1, 4, and 7 MPa. But overall, a pressure of 1 MPa is more conducive for carbon dioxide molecules to enter the hydrate layer and form carbon dioxide hydrates. Adding EG to CO2 molecules can inhibit the decomposition of methane hydrates. However, the higher the concentration of EG, the faster the decomposition of methane hydrates. The degree of fracture of the water cages in methane hydrates is greater under pure CO2 conditions. Adding EG to CO2 molecules is more conducive for CO2 molecules to enter the hydrate layer and form carbon dioxide hydrates. This review is of great significance to improve the mining efficiency and CO2 storage efficiency of the replacement of natural gas hydrates with CO2.

The Role of Chinese Herbs and Acupuncture on the Inflammation Reaction After Cerebral Ischemia.

As a complex pathological process, immune inflammatory reaction plays an important role in the injury by cerebral ischemia. Inflammatory mediators can promote each other to coregulate the immune inflammatory reaction. Inflammatory cytokines play a pivotal role in regulating the immune inflammatory reaction process. Chinese herbs and acupuncture can exert a protective effect against neuronal damage by cerebral ischemia by inhibiting the production and expression of inflammatory cytokines and adhesion molecules, effectively blocking the inflammatory reaction and reducing the apoptosis of nerve cells.

[Discussion on methods for searching traditional Chinese medical literature in English in PubMed-MEDLINE database].

The methods for searching traditional Chinese medical literature in English with subject headings in PubMed-MEDLINE database were discussed from the practical view, and seven useful searching methods with free words according to practical experiences were put forward in order to assist the domestic TCM researchers to utilize PubMed-MEDLINE database in searching overseas TCM literature in English.