Effect of Configuration of Micro-/Nanoscale Structure on Sliding Surface on Molecular Gas-Film Lubrication

Abstract. Nakamori et al. found experimentally that the friction between a partly polished diamond coating and a metal surface was drastically reduced to zero as relative speed increased to a few m/s [Diamond Relat. Mater. 14, (2005), 2122]. It seems that diamond coating took off the counter surface because sliding was noiseless in their experiment. However, the mechanism of this phenomenon was unknown. In the previous work, we performed the numerical simulation of micro-/nanoscale gas flow between two sliding surfaces, i. e., the slider surface with microscale surface roughness like partly polished diamond coating and the flat counter surface. And then, we successfully reproduced lift force large enough to suspend the slider used in the experiment and found that this effect became notable only for micro-/nanoscale gas flow. In the present paper, we investigate the effect of configuration of micro-/nanoscale structure on sliding surface on molecular gas-film lubrication. Since micro-/nanoscale gas flows between two sliding surfaces cannot be treated as a continuum, we use the direct simulation Monte Carlo (DSMC) method

Effect of Configuration of Micro-/Nanoscale Structure on Sliding Surface on Molecular Gas-Film Lubrication

Abstract. Nakamori et al. found experimentally that the friction between a partly polished diamond coating and a metal surface was drastically reduced to zero as relative speed increased to a few m/s [Diamond Relat. Mater. 14, (2005), 2122]. It seems that diamond coating took off the counter surface because sliding was noiseless in their experiment. However, the mechanism of this phenomenon was unknown. In the previous work, we performed the numerical simulation of micro-/nanoscale gas flow between two sliding surfaces, i. e., the slider surface with microscale surface roughness like partly polished diamond coating and the flat counter surface. And then, we successfully reproduced lift force large enough to suspend the slider used in the experiment and found that this effect became notable only for micro-/nanoscale gas flow. In the present paper, we investigate the effect of configuration of micro-/nanoscale structure on sliding surface on molecular gas-film lubrication. Since micro-/nanoscale gas flows between two sliding surfaces cannot be treated as a continuum, we use the direct simulation Monte Carlo (DSMC) method

Formation Processes of Metal-Rich Tribofilm on the Counterface During Sliding Against Metal/Diamondlike-Carbon Nanocomposite Coatings

Formation processes of metal-rich tribofilm on the counterface during sliding against metal/diamondlike-carbon nanocomposite coatings have been investigate. The hybridization between DLC matrix and Cu or Ag provides good electric conductivity to solid lubricant films. Metal-rich tribofilms are formed on the counterface of both Cu-DLC and Ag-DLC during sliding, which is important factor to obtain excellent tribological performance as well as good electric conductivity. Such tribofilms are almost pure Cu and Ag. The origin of the tribofilm is the metal clusters in the Me-DLC, and the adhered Cu and Ag clusters on the counterfaces are possibly sintered and refined during iterative plastic deformation in the frictional interface which generates high pressure and high shear rate

Design Optimization of Noise Filter Using Quantum Annealer

The use of quantum annealers in black-box optimization to obtain the desired properties of a product with a small number of trials has attracted attention. However, the application of this technique to engineering design problems has been limited. Here, we demonstrate the applicability of black-box optimization with a quantum annealer to the design of electric circuit systems, focusing on $\pi$ -type noise filters as an example. We develop a framework that uses quantum annealing to find the optimal location of electrical components and conductor paths connecting the components, and confirm that the learning process appropriately works over a number of trials to efficiently search for a design with high performance. The results show the potential applicability of quantum annealing to design problems of electric circuit systems