National Physical Laboratory

About: National Physical Laboratory is a facility organization based out in London, United Kingdom. It is known for research contribution in the topics: Dielectric & Thin film. The organization has 7615 authors who have published 13327 publications receiving 319381 citations.

Fluid Film Lubrication of Parallel Thrust Surfaces

Abstract: During the course of an investigation into the general characteristics of various types of thrust bearing, it has been shown that opposed parallel surfaces, under certain conditions of operation, have a load carrying capacity approaching that of tilting pad bearings of the Michell type and of the same bearing area. Considerable evidence has been obtained, such as the low friction losses, the dependence of coefficient of friction on viscosity, speed and load, and the apparent absence of metallic contact, which strongly indicates that these bearings operate under fluid film conditions. Their performance does not seem to depend on a rounded inlet edge, and the apparent establishment of fluid film conditions without the usually accepted requirement of convergence of the bearing surfaces is regarded as a new phenomenon in lubrication. A tentative theory on broad lines is suggested as an explanation of the behaviour.

Structural, optical and electrostatic properties of single and few-layers MoS 2 : effect of substrate

Abstract: We have decoupled the intrinsic electrostatic effects arising in monolayer and few-layer MoS2 from those influenced by the flake-substrate interaction. Using ultrasonic force microscopy nanomechanical mapping, we identify the change from supported to suspended flake regions on a trenched substrate. These regions are correlated with the surface potential as measured by scanning Kelvin probe microscopy. Relative to the supported region, we observe an increase in surface potential contrast due to suppressed charge transfer for the suspended monolayer. Using Raman spectroscopy we observe a red shift of the E12g mode for monolayer MoS2 deposited on Si, consistent with a more strained MoS2 on the Si substrate compared to the Au substrate.