scholarly journals Simulation of the desorption process of methane adsorbed in a coal rock, taking into account intermolecular sorption interactions in the system “methane-coal”

2019 ◽  
Vol 109 ◽  
pp. 00073
Author(s):  
Alla Prusova ◽  
Oleksandr Minieiev ◽  
Svitlana Ryzhova
Keyword(s):  
Analytical Calculation ◽  
Activation Process ◽  
Mining Operations ◽  
Desorption Process ◽  
Jones Potential ◽  
Lennard Jones ◽  
Geological Conditions ◽  
Coal Rock ◽  
Nonequilibrium Sorption ◽  
Kinetics Of

Based on the analysis of the stages of the desorption of methane adsorbed in the coal rock, the simulation of this process was based on its consideration as an activation process of diffusion. It was found that the intermolecular sorption interactions in the “methane-coal” system should be described by the Lennard-Jones potential, taking into account the polymeric nature of the molecular structure of coal. Therefore, an analysis of the modern theories of the kinetics of nonequilibrium sorption processes in high-molecular materials was performed. This analysis showed that the complex of the main molecular factors in the system “methane – coal” can be taken into account most correctly using the Pace – Deutiner molecular parameters. The diffusion coefficient in the equation takes into account the activation energy of the diffusion process, intermolecular sorption interactions in the “methane-coal” system, the parameters of the microstructure of coal, the physical properties of methane and the magnitude of its diffusion jump. The analytical calculation of the diffusion equation is carried out. It allows determining the patterns of the desorption process in various geological conditions of mining operations.

scholarly journals Inferring Single-Cell 3D Chromosomal Structures Based on the Lennard-Jones Potential

2021 ◽  
Vol 22 (11) ◽  
pp. 5914
Author(s):  
Mengsheng Zha ◽  
Nan Wang ◽  
Chaoyang Zhang ◽  
Zheng Wang
Keyword(s):  
Single Cell ◽  
Loss Function ◽  
Gaussian Function ◽  
Three Dimensional ◽  
Lennard Jones Potential ◽  
Jones Potential ◽  
Cubic Lattice ◽  
Lennard Jones ◽  
3D Fish ◽  
Well Depth

Reconstructing three-dimensional (3D) chromosomal structures based on single-cell Hi-C data is a challenging scientific problem due to the extreme sparseness of the single-cell Hi-C data. In this research, we used the Lennard-Jones potential to reconstruct both 500 kb and high-resolution 50 kb chromosomal structures based on single-cell Hi-C data. A chromosome was represented by a string of 500 kb or 50 kb DNA beads and put into a 3D cubic lattice for simulations. A 2D Gaussian function was used to impute the sparse single-cell Hi-C contact matrices. We designed a novel loss function based on the Lennard-Jones potential, in which the ε value, i.e., the well depth, was used to indicate how stable the binding of every pair of beads is. For the bead pairs that have single-cell Hi-C contacts and their neighboring bead pairs, the loss function assigns them stronger binding stability. The Metropolis–Hastings algorithm was used to try different locations for the DNA beads, and simulated annealing was used to optimize the loss function. We proved the correctness and validness of the reconstructed 3D structures by evaluating the models according to multiple criteria and comparing the models with 3D-FISH data.

Raman spectra and lattice dynamics of the α phases of nitrogen and carbon monoxide crystals

1970 ◽  
Vol 48 (19) ◽  
pp. 2265-2271 ◽  
Author(s):  
A. Anderson ◽  
T. S. Sun ◽  
M. C. A. Donkersloot
Keyword(s):  
Carbon Monoxide ◽  
Raman Spectra ◽  
Lattice Dynamics ◽  
Jones Potential ◽  
Lennard Jones ◽  
Neon Laser ◽  
Helium Neon Laser ◽  
First Time ◽  
Helium Neon ◽  
Argon Ion

The Raman spectra of polycrystalline α-nitrogen and α-carbon monoxide have been recorded at 18 °K, using argon–ion and helium–neon laser excitation. Previously undetected peaks at 60 cm−1 for N2 and 90.5 cm−1 for CO are assigned as librational modes, and splitting of the stretching mode in nitrogen is observed for the first time. Spectral features in both the intramolecular and lattice regions are assigned in accordance with accepted crystal structures, and their frequencies compared with those obtained from calculations based on a spherical Lennard–Jones potential and quadrupole–quadrupole interactions between the molecules.

Mechanical and Tribological Properties of Carbon Nanotubes Investigated with Atomistic Simulations

2000 ◽  
Vol 633 ◽  
Author(s):  
Boris Ni ◽  
Susan B. Sinnott
Keyword(s):  
Carbon Nanotubes ◽  
Atomistic Simulations ◽  
Many Body ◽  
Jones Potential ◽  
Diamond Surfaces ◽  
Empirical Potential ◽  
Mechanical And Tribological Properties ◽  
Lennard Jones ◽  
Walled Carbon Nanotubes ◽  
Nanotube Bundle

AbstractAtomistic simulations are used to better understand the behavior of bundles of single- walled carbon nanotubes that have been placed between two sliding diamond surfaces. A many-body reactive empirical potential for hydrocarbons that has been coupled to a Lennard-Jones potential is used to determine the energies and forces for all the atoms in the simulations. The results indicate that the degree of compression of the nanotube bundle between the nanotubes has a significant effect on the responses of the nanotubes to shear forces. However, no rolling of the nanotubes is predicted in contrast to previous studies of individual nanotubes moving on graphite.

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