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The improved Tosi–Fumi pair potential has been employed to simulate the melting behavior and Grüneisen parameters of sodium chloride (NaCl) using molecular dynamics (MD) method at constant volume. The melting curve of NaCl is compared with the experimental data and other calculations in a pressure range from 0 to 144 GPa. The simulated results validate the amount of 20% superheating of the NaCl solid and yield an approximate power law dependence of the Grüneisen parameter (γ) on compression γ = γ₀(V/V₀)^q, with q ≈ 1.078, in the temperature range from 298 to 1073 K and pressure range from 0 to 60 GPa.

In this paper, we have carried out a theoretical investigation on the structural and optoelectronic properties of NaCl under pressure effect via first principle calculations within the density functional theory. The structural phase transition from NaCl(B1) to CsCl(B2)-type structures is determined. The compound has a very wide bandgap in both phases. Optical properties including the absorption coefficient, optical conductivity and frequency dependent reflectivity are explained to characterize the optical nature of NaCl up to pressure of 134 GPa.

Subsea tunnel construction is usually associated with high risk due to high water pressure. To ensure the safety of the tunnel during construction, artificial ground freezing (AGF) technology is typically adopted to freeze the surrounding soil of the tunnel. Previous researches reveal that the strength properties of clay vary significantly due to the coupling effect of salt and freeze–thaw. For this reason, the consolidated-undrained triaxial compression test was carried out on clay saturated with NaCl solution. The influences of freeze–thaw cycle, salt content, confining pressure, and strain rate on the strength were comprehensively evaluated. A statistical analysis was performed to distinguish the influence of these factors and their coupling effect. Test results reveal that a critical salt content exists at which the soil strength before and after a freeze–thaw cycle is the lowest. Similarly, instead of linearly increase with increasing strain rate, a critical strain rate exists at which the soil strength is the highest under undrained loading. In addition, a damage model with consideration of the coupling effect of freeze–thaw cycle and salt content was specially proposed to predict the stress–strain characteristic of clay with different salt contents before and after a freeze–thaw cycle.

Natural graphite is a soft material that conventional milling methods fail to grind into nanoparticles. We found that adding NaCl into graphite during milling allows obtaining graphene nanoflakes of about 50$\times$200nm² as evidenced by Transmission Electron Microscope (TEM). NaCl particles are substantially brittle and harder than graphite, serving as milling agents by both helping to chop graphite into smaller pieces and preventing graphite particles from agglomeration. After milling, NaCl can be easily washed away by water. Probable mechanism for exfoliation of graphene during the modified ball milling may be explained by NaCl and graphene slipping or sliding against and over each other, exfoliating the graphene particles into thin layers.

Taking seeds of Cichorium intybus L. as materials, using the method of germination in petri dish, effect on C. intybus L. seeds germination under different concentrations of NaCl, NaHCO₃ solution and both 1:1 mixed solution stress and after the stress being removed was studied, in order to investigate salinity tolerance ability of C. intybus L. seeds. The results showed that seed germination rate, germination potential and relative germination rate was decreased with NaCl, NaHCO₃ and both 1:1 mixed concentration was increased. At high concentration, the inhibitory effect of seed was the most significant. The optimal, critical and limit value of NaCl that affected relative germination rate was 3.509‰, 5.644‰, 7.779‰; these of NaHCO₃ concentration was 3.448‰, 5.736‰, 8.023‰ and these of both 1:1 mixed concentration was 4.076‰, 6.654‰, 9.232‰. The results of relief stress suggested that seeds stressed of higher concentration of NaCl, NaHCO₃ and both 1:1 mixed still had greater germination capacity especially, it showed the seeds of C. intybus L. had stronger resistance to salt and alkali.