Molecular Dynamics Simulation of the Three-Phase Equilibrium Line of CO Hydrate with OPC Water Model.

The three-phase coexistence line of the CO hydrate was determined using molecular dynamics (MD) simulations. By using the classical and modified Lorentz-Berthelot (LB) parameters, the simulations were carried out at 10 different pressures from 3 to 500 MPa. For the OPC water model, simulations with the classic and the modified LB parameters both showed negative deviations from the experimental values.

The performance of OPC water model in prediction of the phase equilibria of methane hydrate.

Molecular dynamics (MD) simulations were performed to determine the three-phase coexistence line of sI methane hydrates. The MD simulations were carried out at four different pressures (4, 10, 40, and 100 MPa) by using the direct phase coexistence method. In current simulations, water was described by either TIP4P/Ice or "optimal" point charge (OPC) models and methane was described as a simple Lennard-Jones interaction site.

Discovery of supercritical carbon dioxide in a hydrothermal system.

Supercritical CO appearing as bubbles in hydrothermal vents was identified in the south part of the Okinawa Trough using in situ Raman spectroscopy. Significantly, the N peak in supercritical CO is much larger than those in seawater and vent fluids, indicating that supercritical CO enriches N from the surrounding environment. Considering that the partial pressures of CO and N in the Earth's proto-atmosphere were ~10-20 MPa, supercritical CO with high N was likely the dominant CO phase near the water-air interface in the early history of the Earth, which promoted the synthesis, pre-enrichment and preservation of amino acids and other organic matters that are essential to the origin of life.

Microscopic study on the concretion of ceramics in the "Nanhai I" shipwreck of China, Southern Song Dynasty (1,127-1,279 A.D.).

"Nanhai I" shipwreck of China Southern Song Dynasty is the oldest and the most integrally preserved shipwreck in the world. The related conservation and archeological research have caught great attention of different experts all over the world. In this study, different types of concretion covered on the surface of the ceramics in "Nanhai I" shipwreck were analyzed by X-ray diffractometer, micro-Raman spectrometer, and scanning electron microscope equipped with energy dispersive spectroscopy.