Microscopic mechanism of ultrashort-pulse laser ablation of metals: a molecular dynamics study incorporating electronic entropy effects

The microscopic mechanism of metal ablation induced by ultrashort laser pulse irradiation is investigated. A two-temperature model scheme combined with molecular dynamics (TTM-MD) is developed to incorporate electronic entropy effects into the simulation of metal ablation while satisfying the energy conservation law. Simulation with the TTM-MD scheme reveals that ultrashort laser pulse irradiation near the ablation threshold causes high-energy ion emission and sub-nanometer depth ablation, as observed experimentally, due to the electronic entropy effect. It is also shown that the electronic entropy effect is also significant in spallation.Comment: 13 pages, 18 figure

Observation of Plasma Hole in an ECR Ar Plasma

The first experimental observation of a plasma hole structure in an ECR argon plasma is reported. The plasma hole is a cylindrical density cavity, which is formed spontaneously in the center of the plasma. The steep density gradient between the hole plasma and the ambient plasma is sustained by a thin interfacial layer, the width of which is a few ion Larmor radii. Supersonic rotation is found over the large cross-sectional area of Ar plasma hole. The axial flow can also exceed ion sound speed. Spectral measurements revealed that the neutral density profile exhibits a hole structure as well as that in ion density, the diameter of which is much shorter than the mean free path of neutral particles

"Coeur resonant" : Online Hospital Art Creation with People in the Distance

Authors have created several hospital arts using masking tape with Tokushima University Hospital Art Labo (THAL). To enhance the value more, we collaborated with a professional artist, Koichi Nishimura who create large hearts on public institutions. Furthermore, a global financial institution, BNP Parisbas group, provided financial support and incorporate social action program. The art work "Coeur resonant (Resonant Heart)" was completed in Tokushima Red Cross Hospital, including 220 small hearts on film sheets from 145 collaborators. The entire making process was supervised using online system. Current approach suggests new method for many people to participate in hospital art

Psychologically comfortable seasonal images for the project on the art in hospitals

Historically speaking, hospitals had grown out of hostels, where pilgrims, old and sick people were treated. During the Middle Ages in Europe, the art was indispensable factor of the hospitals. Art in hospitals (hospital art) has been recently known and recognized as beneficial method. Authors performed the art in hospitals in the rehabilitation hospital, which was completed by using various colorful masking tape. The composition consisted of 4 artworks for four seasons on the wall of the corridor. Many patients are trained walking with always looking them every day. Art in hospitals may be called as art and health, and it has a power to make patients bring out positive attitude and energy. Its further development would be expected