Showing papers by "George Davey Smith published in 1981"
TL;DR: In this paper, the apparent concentration of silicon is found to depend on pulse fraction, time between pulses, specimen temperature, and crystallographic area, and it appears that a pulse fraction of at least 15% is required and that analysis inside the central ring of low index poles should be avoided.
Abstract: In some atom probe microanalytical investigations of homogeneous alloys, the apparent concentrations of certain elements have been found to differ from the expected values. Both the time of flight atom probe and the imaging atom probe have been used to study this phenomenon in detail, in the case of an iron 3 wt.% silicon transformer steel. The apparent concentration of silicon is found to depend on pulse fraction, time between pulses, specimen temperature, and crystallographic area. Low pulse fractions and long periods between pulses both give apparent increases in the silicon level. When the probe aperture is positioned inside the central ring of a (110) pole, the silicon atoms are found to be retained until the end of the evaporation of that layer, and the overall apparent level of silicon is approximately three times higher than expected. These results suggest that certain elements may be preferentially removed from an alloy by dc field evaporation during the interval between the H. T. pulses if incorrect experimental conditions are used. For quantitative atom probe analysis of silicon‐containing alloys, it appears that a pulse fraction of at least 15% is required and that analysis inside the central ring of low index poles should be avoided.
75 citations
TL;DR: Barnard, G.W. Smith, M. Sarikaya, and G.J. Thomas as discussed by the authors presented the CARBON ATOM DISTRIBUTION in a DUAL PHASE STEEL: AN ATOM PROBE STUDY.
45 citations
TL;DR: The effects of atropine and metoclopramide on the lower oesophageal sphincter pressure (LOSP) were studied in 12 healthy volunteers using oesophileal pressure transducers.
Abstract: The effects of atropine and metoclopramide on the lower oesophageal sphincter pressure (LOSP) were studied in 12 healthy volunteers using oesophageal pressure transducers. Atropine decreased LOSP significantly at 5mm after i.v. injection ( P P
32 citations
TL;DR: Lower oesophageal sphincter pressure (LOSP) has been measured on three separate occasions in nine healthy volunteers using oesophileal pressure transducers and the change was similar for both doses and also similar in magnitude to the change produced by atropine.
Abstract: Lower oesophageal sphincter pressure (LOSP) has been measured on three separate occasions in nine healthy volunteers using oesophageal pressure transducers. Atropine 0.6mg decreased LOSP signifi candy at 5mm after iv. injection (P
23 citations
TL;DR: The effect of diazepam 10 mg orally was investigated on lower oesophageal sphincter pressure in a random double-blind study of nine healthy volunteers and Barrier pressure decreased to a small but statistically significant extent.
Abstract: The effect of diazepam 10 mg orally was investigated on lower oesophageal sphincter pressure in a random double-blind study of nine healthy volunteers. Barrier pressure decreased to a small but statistically significant extent. The reduction in barrier pressure was not related to the level of drowsiness.
9 citations
TL;DR: In this paper, the Burgers vectors of the dislocations comprising the network have been determined to be of the type a/3(211), and it was shown that these correspond to those of the perfect grain boundary Dislocations predicted by DSC lattice theory for this boundary.
Abstract: The techniques of field ion microscopy and transmission electron microscopy have been used to investigate an incoherent twin boundary in tungsten in which a small (∼1°) twist misorientation is accommodated by a hexagonal network of screw dislocations. The Burgers vectors of the dislocations comprising the network have been determined to be of the type a/3(211), and it is shown that these correspond to those of the perfect grain boundary dislocations predicted by DSC lattice theory for this boundary. It is also demonstrated that if any rigid body translation is associated with the boundary, its magnitude is such that it is below the resolution of the FIM technique (<0.3 A).
8 citations