The effect of applying a rounded stylus to thin metallic films on glass substrates has been investigated using diamond and steel styli with tip radii of approximately 25 μm and loadings of up to 230 g. The films were vacuum-deposited indium, tin, lead, gold, copper, aluminium, nickel, chromium and molybdenum of various thicknesses up to 3·2 μm. Scanning electron microscope and optical interference microscope observations showed that the process of scratch formation was generally very complex and varied with the film material, indicating that it is not possible to deduce absolute values of adhesion forces using a simple general theoretical model. The method can, however, be used with caution for qualitative comparisons under certain restricted conditions.
The effect of oxygen, present during film formation, on the structure and superconducting properties of tin films vacuum deposited on glass has been studied for substrate temperatures during deposition in the ranges of 23-30°C and 63-91°C.In both temperature ranges, in general, an increase in oxygen pressure decreases crystallite size and electron mean free path; it increases superconducting critical magnetic field value and width of transition but decreases the superconducting temperature transition width.The higher substrate temperatures produce films with larger crystallites and thin intercrystalline regions; these show hysteresis in the superconducting magnetic field transition and have higher values of critical field and critical current, in excess of those theoretically predicted.
Summary
The scanning electron microscope has been used to compare the microstructure of an old grassland soil with that of an arable soil of the same soil series. The micrographs give more direct evidence than previously available of the presence of an adherent, presumably organic, matrix binding the clay and other particles of the old grassland soil. Fungal hyphae were also observed. Neither of these features was present to the same extent in the old arable soil.
Results are summarized from thirteen laboratories which took part in the first four phases of an international intercomparison of pressure measurement standards in the range 10 kPa to 140 kPa, carried out under the auspices of the BIPM. The transfer standard was a gas-operated pressure balance (piston gauge). All participants took measurements in the absolute mode; several also took measurements in the gauge mode. The transfer standard showed good repeatability and long-term stability, and revealed some unexpected and significant differences between some of the participants.
Following the advent of the BIPM Recommendation of 1981 and the IS0 Guide of 1993, it should be possible to achieve much greater consistency in the ways in which the measurement uncertainties of pressure standards are evaluated and expressed. These documents divide uncertainty contributions into two groups, type A (random) and type B (others). The method of evaluating and combining uncertainty contributions is illustrated by two examplesa U-tube manometer and a pressure balance (piston gauge). In both cases the uncertainty contributions are subdivided into two further groups -those which are independent of the applied pressure and those which are proportional to it.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.