Electronic friction in interacting systems

We consider effects of strong light-matter interaction on electronic friction in molecular junctions within generic model of single molecule nano cavity junction. Results of the Hubbard NEGF simulations are compared with mean-field NEGF and generalized Head-Gordon and Tully approaches. Mean-field NEGF is shown to fail qualitatively at strong intra-system interactions, while accuracy of the generalized Head-Gordon and Tully results is restricted to situations of well separated intra-molecular excitations, when bath induced coherences are negligible. Numerical results show effects of bias and cavity mode pumping on electronic friction. We demonstrate non-monotonic behavior of the friction on the bias and intensity of the pumping field and indicate possibility of engineering friction control in single molecule junctions.Comment: 19 pages, 4 figure

Current-induced forces for nonadiabatic molecular dynamics

We present general first principles derivation of expression for current-induced forces. The expression is applicable in non-equilibrium molecular systems with arbitrary intra-molecular interactions and for any electron-nuclei coupling. It provides a controlled consistent way to account for quantum effects of nuclear motion, accounts for electronic non-Markov character of the friction tensor, and opens way to treatments beyond strictly adiabatic approximation. We show connection of the expression with previous studies, and discuss effective ways to evaluate the friction tensor.Comment: 6 pages, 3 figure

Application of CMC materials into aero-engines

IHI is one of the oldest companies in Japan. It started in 1853 as a shipbuilding company, but it has produced aero-engines since 1957. At an early stage in aero-engine business, IHI was producing military engines mainly. But IHI participated in commercial engine business in 1980’s as a partner of international joint development team. Since then, business scale has grown to 4 billion dollars of annular sales. It is expected that aero-engine market continues to grow by 4 to 5% per year. However, there are several problems to solve such as environmental regulation tightening, restriction in number of aircraft departure and landing on airport and increase in number of low cost carriers with financially weakness. In order to solve these problems, aero-engines have to evolve into system with lower fuel burn, more environmental suitability, larger thrust and lower lifecycle cost. There are several candidates to solve the problems, but it is certain that application of lighter and higher temperature resistant materials is one of solutions. We introduce our products and R&D activities for composite material technologies as a solution for the above-mentioned problems. The composite material technology means not only material but also design and manufacturing. IHI concentrates on light CFRP for fan module and light and heat resistant CMC for turbine module in aero-engines. Regarding CFRP, we have both of thermoset type and thermo-plastic type. The former was applied into fan case and the latter into fan structural guide vane. They became products supplied with PW1100G engine for Airbus A320neo. On the other hand, CMC technology is under development for military and commercial engines. Our CMC manufacturing process is as follows. SiC fibers are processed on BN interface coating. BN coated fibers are weaved into 3D woven fabric. CVI, PIP and SPI process infiltrate matrix into 3D woven fabric. SPI is solid particle infiltration. After that, it is machined and finally EBC coated. Positive feature of our material is superiority in heat and impact resistance. Technology validation was conducted on in-house small gas turbine named IM270 for electric power generation. Next validation test will be conducted on a two-shaft turbo-fan aero-engine to be introduced to JAXA in a few years. CMC technology development has been supported by government funding from METI, NEDO, SIP and JAXA