Blog posts

In this letter we obtain the finite-temperature structure

of 180^o domain walls in PbTiO_3 using a quasi-harmonic

lattice dynamics approach. We obtain the temperature dependence of

the atomic structure of domain walls from 0 K up to room

temperature. We also show that both Pb-centered and Ti-centered

180^o domain walls are thicker at room temperature; domain

wall thickness at T=300 K is about three times larger than that of

T=0 K. Our calculations show that Ti-centered domain walls have a

This month's issue of SIAM news had a beautiful story of how one hard problem in mathematics was solved in less than six weeks using online collaboration. SIAM's story is not online yet, but here is another link to the same story .   SIAM news refers to a "super-mathematician" coming out of several individual mathematician spread all over the world.

Nanovea is proud to announce the installation of a Nano/Micro Mechanical Tester at Technische Universitat Munchen (Technical University of Munich, DE). The instrument was installed in the Department of Civil Engineering & Surveying at the CBM Center for Building Materials. The unique Nano and Micro modular capabilities of the Nanovea Mechanical Tester was chosen over several competitors. The instrument will be used to further industrial research in the mechanical behaviors of concrete and cementitious binder technology among others.

These notes belong to a course on fracture mechanics

Lecture 1 introduced the crack bridging model. The model is also known as the cohesive-zone model, the Barenblatt model, or the Dugdale model. The model consists of two main ingredients:

The School of Mechanical and Aerospace Engineering in Nanyang Technological University, Singapore, is looking for a highly motivated researcher for a three-year Post-doctoral Fellowship in the area of atomistic/molecular dynamics modelling.

The research project is computational based and will focus on the atomistic modelling of lubricant and diamond-like carbon. The work will include molecular dynamics simulations, code programming and publications of research papers. The successful candidate will also have to work closely with scientists from A*STAR.

In this manuscript (available at http://arxiv.org/abs/1004.1765), we present a systematically improvable, linear scaling formulation for the solution of the all-electron Coulomb problem in crystalline solids. In an infinite crystal, the electrostatic (Coulomb) potential is a sum of nuclear and electronic contributions, and each of these terms diverges and the sum is only conditionally convergent due to the long-range 1/r nature of the Coulomb interaction.

In the study of thermoelastic actuation of dielectric elastomer, we can write the Helmholtz free-energy as a function of stretch ratio, nominal electric displacement and temperature (T).

The entropy (S) is the negative partial differential coefficient of W with respect of temperature (T). And we can see the change of S is due to three components: deformation, heat conduction and polarization. In an isothermal state, the deformation part has been fully investigated by Arruda and Boyce in 1993, but the polarization-induced entropy (Sp) has not been clearly stated.