Showing papers by "Yang-Tse Cheng published in 1997"

On the initial unloading slope in indentation of elastic-plastic solids by an indenter with an axisymmetric smooth profile

Abstract: A simple relationship between the initial unloading slope, the contact area, and the elastic modulus is derived for indentation in elastic-plastic solids by an indenter with an arbitrary axisymmetric smooth profile Although the same expression was known to hold for elastic solids, the new derivation shows that it is also true for elastic-plastic solids with or without work hardening and residual stress These results should provide a sound basis for the use of the relationship for mechanical property determination using indentation techniques

Thin film hydrogen sensor

Abstract: A thin film hydrogen sensor, includes: a substantially flat ceramic substrate with first and second planar sides and a first substrate end opposite a second substrate end; a thin film temperature responsive resistor on the first planar side of the substrate proximate to the first substrate end; a thin film hydrogen responsive metal resistor on the first planar side of the substrate proximate to the fist substrate end and proximate to the temperature responsive resistor; and a heater on the second planar side of the substrate proximate to the first end.