It is very important to theoretically analyse and numerically simulate the ground stability of welded structures, which are of recent worldwide interest.

Packing density and confining pressure have a great effect on the mechanical behavior of sand. Therefore, several kinds of models have been proposed and each of them has their own features.

Fabric anisotropy variable and density function also have a great effect on the mechanical property of anisotropic sand.

Jong Yong Kwang, a researcher at the Faculty of Material Science and Technology, based on the anisotropic critical state theory (ACST), developed a modified anisotropic hypoplastic model by incorporating the relation between fabric anisotropy variable and density function into the nonlinear part of the constitutive model.

He validated the applicability of the improved model by comparing it with the existing model and experimental data.

The results showed that the modified model can well predict the critical state response of anisotropic sand.

You can find more information in his paper “An Anisotropic Critical State Hypoplastic Model Considering the Relation Between Fabric Anisotropy Variable and Density Function” in “Mechanics of Solids” (SCI).

If further information is needed, please refer to his paper “Atomic insights into the material properties of double-perovskite-type hydride LiNaMg₂H₆ for H₂ storage applications” in “RSC Advances” (SCI).

Transparent conducting oxide (TCO) films have been widely used as transparent electrodes in the optoelectronic devices such as flat panel displays and thin-film solar cells. Among them, Al-doped ZnO (AZO) films are being studied most due to their rich resources of Al and good electrical and optical properties.

The sputtering ambient has an influence on the microstructure, composition and electrical and optical properties of ZnO based films deposited by sputtering.

Some studies showed that adding appropriate amount of H₂ into sputtering ambient leads to enhancement of the electrical properties of films. This encouraged many attempts to improve the properties of doped ZnO films by adding H₂. However, there is little literature that dealt with the effects of H₂ content on the properties of doped ZnO films deposited at low temperature and at high temperature.

Ri Kang Hyon, a section head at the Faculty of Material Science and Technology, compared the influence of H₂ addition to sputtering ambient on the microstructural and electrical properties of AZO films deposited by r.f. magnetron sputtering at low temperature (100 ℃) and high temperature (400 ℃).

The results showed that for the AZO films prepared at comparatively low temperature around 100 ℃, small addition of H₂ to sputtering ambient was favorable for enhancing the electrical properties of films, but for those at high temperature around 400℃, any addition of H₂ was unfavourable at all.

For more information, please refer to his paper “Influence of hydrogen addition to sputtering ambient on the properties of AZO films deposited by sputtering” in “Physica Scripta” (SCI).