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Simultaneous measurements of interdiffusion and intrinsic diffusion coefficients in liquid Sn-Pb were performed using the shear cell method and a stable density layering. The binary diffusion couples of Sn-Pb and Sn0.6Pb0.4-Sn0.4Pb0.6 were used in two experiments with the average molar fraction of diffusion couples NSn = 0.5. The concentration dependency of the interdiffusion coefficient was confirmed to exhibit a downward convexity through the comparison of the interdiffusion coefficients. However, the Boltzmann–Matano method reveals a diminished influence. The sample measurements of the intrinsic diffusion coefficients of a diffusion couple of pure metals demonstrate a dependency on concentration. On the other hand, the difference of diffusion coefficients was small in a diffusion couple of alloys. The difference between the values calculated by fitting the error function based on the superposition of fluxes and by the conventional analysis methods was small. We propose that a reasonable intrinsic diffusion coefficient can be calculated using the superposed equation of error function. The theoretical interdiffusion coefficients were calculated by substituting the measured intrinsic diffusion coefficients into the Darken’s equation and comparing the results with the measured values. As a result, the difference between the theoretical and measured interdiffusion coefficients is not very large.

By utilizing the shear cell technique and achieving stable density layering with the addition of an alloying element Bi, the self-diffusion coefficients of liquid Sn were measured on the ground at 573 K, 773 K, and 973 K (300 °C, 500 °C, and 700 °C). Moreover, the impurity diffusion coefficients of Bi in the liquid Sn were simultaneously measured, to confirm the suppression of natural convection. From the experimental results, natural convection was confirmed to be suppressed, given that the impurity diffusion coefficients of Bi were in good agreement with the microgravity reference data. Upon changing the amounts of added Bi within 5 at. pct Bi, the self-diffusion coefficients of liquid Sn did not vary significantly. Moreover, the SnBi system within 5 at. pct Bi can be regarded as a dilute solution by calculating the activity of Sn in the SnBi system beforehand. The self-diffusion coefficients of the liquid Sn were in good agreement with the power law of temperature dependence from the microgravity reference data. After confirming the suppression of natural convection and that the SnBi system is a dilute solution, the self-diffusion coefficient of liquid Sn was determined as 5.00 ± 0.16 × 10−9 m2 s−1 at 773 K (500 °C). The effectiveness of the experimental method used in this study for the measurement of the self-diffusion coefficients was confirmed, under the condition that the liquid system could be regarded as a dilute solution.

Band gap opening of a single-layer graphene nanoribbon (sGNR) sitting on another sGNR, fabricated by drop casting GNR solution on Au(111) substrate in air, was studied by means of scanning tunneling microscopy and spectroscopy in an ultra-high vacuum at 78 K and 300 K. GNRs with a width of ~45 nm were prepared by unzipping double-walled carbon nanotubes (diameter ~15 nm) using the ultrasonic method. In contrast to atomically-flat GNRs fabricated via the bottom-up process, the drop cast sGNRs were buckled on Au(111), i.e., some local points of the sGNR are in contact with the substrate (d ~ 0.5 nm), but other parts float (d ~ 1–3 nm), where d denotes the measured distance between the sGNR and the substrate. In spite of the fact that the nanoribbons were buckled, dI/dV maps confirmed that each buckled sGNR had a metallic character (~3.5 Go) with considerable uniform local density of states, comparable to a flat sGNR. However, when two sGNRs crossed each other, the crossed areas showed a band gap between −50 and +200 meV around the Fermi energy, i.e., the only upper sGNR electronic property changed from metallic to p-type semiconducting, which was not due to the bending, but the electronic interactions between the up and down sGNRs.