Previous papers suggested an end processing function, an enhanced smooth continuous condition and a method to overcome the defects of the precedent modified analytic embedded atom method (EAM) potentials considering the farther neighbor atoms by fitting model parameters to one or two structure energy differences. The structure energy differences and the binding energy curves as a function of volume calculated by these potentials are better than the calculation results by precedent modified analytic EAM (MAEAM) considering the farther neighbor atoms in the agreement with the experimental results and the Rose equation curves. The original MAEAM proposed only one many-body potential form for body-centered cubic (BCC), facet-centered cubic (FCC) and hexagonal close packed (HCP) metals. So, this potential has been frequently used in the calculation of the properties of metals and alloys. However, as the MAEAM considering farther neighbor atoms suggested different potential forms for different structures, using this potential is inconvenient and the application examples are rare. But it still gives better results than the original MAEAM.

Therefore, it is necessary to adopt a common potential form which can be applied to all kinds of metals such as the original MAEAM, simultaneously considering the farther neighbor atoms.

Ho In Chol, a researcher at the Faculty of Information Science and Technology, suggested a common pair potential form which can be applied to the three kinds of the typical structures of metals and explain the structure stabilities, the structure energy differences and the dependence of binding energies on lattice constants well.

The results by the common-form potentials of the modified EAM for the BCC transition metals Cr, Fe and Mo are in good agreement with experimental data and other calculation results, and significantly better than the precedent potentials for the BCC metals.

For further details, please refer to his paper “Common potential form of modified embedded atom method and BCC transition metals Cr, Fe, and Mo” in “Indian Journal of Physics” (SCI).

With the rapid development of nanotechnology, nano-composites with nano-additive agents play an important role in many fields. Nano additive agents take various types and some of them are embedded in the surface of the material to enhance its strength or hardness. Therefore, the studies for understanding the mechanical behavior of nano-inclusions in media are increasing day by day.

The scattering of SH waves was often applied to study the dynamic response around the different kinds of inclusions in the half space. From the preceding investigation results, it can be seen that the studies of the surface/interface effects on the dynamic behavior of inclusions are restricted to the circles. Furthermore, the researches on the effects based on the scattering theory of SH waves have been done much less than others.

Jang Paek San, a researcher at the Institute of Nano Science and Technology, investigated the scattering of SH waves by a semi-circle nano-inclusion embedded in the half space surface using the surface/interface elastic theory.

The numerical simulations showed the following. First, as the size of the inclusion decreases to a nanoscale, the value of DSCF (dynamic stress concentration factor) also decreases, which means that the interface effect tends to suppress the perturbation of the DSCF. Second, when the nano addition agents are added into the surface of a medium, the rigidity of the nano-inclusion should be much smaller than that of the medium. Third, in the case of nanoscale inclusion, the surface/interface effect should be considered.

You can find the details in his paper “Dynamic Stress around a semi-circle nano-inclusion embedded in the half space surface” in “Journal of the Brazilian Society of Mechanical Sciences and Engineering” (SCI).

Determination of uranium is very important for effective use of seawater. Uranium is the most stable of all the elements in the ocean. The concentration and pH of uranium in the seawater differ a little according to the region and the depth, but the averages are 3.3×10^-6g/L and 8, respectively.

Yun Chol Hun, a researcher at the Institute of Analysis, has reported a new combined method for the determination of trace uranium in seawater.

First, he added ferric chloride to 1L of seawater sample and adjusted the pH to 4. Then, he placed the solution at 80℃ for 30 min to coprecipitate uranium with iron hydroxide. After that, he dissolved the precipitate in nitric acid and electrodeposited it in EMIMBF₄ to determine uranium by ICP-OES.

He evaluated the coefficient of diffusion (D) of electrodeposition of U(VI) on platinum electrode in EMIMBF, which was 3.31×10⁻⁹cm²/s. The electrochemistry experiments indicated that the reduction of U(VI) at platinum electrode in EMIMBF₄ was a quasi-reversible single step two-electron transfer. The percent of chemical coprecipitation recovery of U(VI) was 98.9% and the recovery in electrodeposition was 99.5%.

For more information, please refer to his paper “Determination of uranium in seawater using chemical coprecipitation-ionic liquid electrodeposition by ICP-OES” in “Journal of Radioanalytical and Nuclear Chemistry” (SCI).