Volume 75, Issue 6, June 2004
Index of content:
75(2004); http://dx.doi.org/10.1063/1.1753682View Description Hide Description
Bending sample methods, like surface stress induced optical deflection, are powerful tools for the in situ determination of thin film and surface stress: the bending radius of a sample is measured via the deflection of reflected laser beams. In most setups split-segment position sensitive detectors are used. A precise method for calibrating those detectors is presented.
75(2004); http://dx.doi.org/10.1063/1.1711190View Description Hide Description
This work presents a design and two methods, one isothermal and one isovolumetric, for pressure measurements based on the compressibility coefficient (κ) and thermal expansibility (α) of the fluid under test. The setup and relevant construction details are described. To demonstrate the applicability of the isovolumetric measurement method, the setup was calibrated with respect to a Bourdon-type manometer; the other isothermic method was analyzed to determine construction details that could realize resolution requirements. The authors determined the effect of ambient temperature on device operation and the time response of the isovolumetric method. The device can be used to estimate the compressibility of a fluid and, in addition, could become an alternative for direct plant cell turgor measurement.
75(2004); http://dx.doi.org/10.1063/1.1753094View Description Hide Description
A wide frequency range, analog in-phase/quadrature generator was developed for use in synchronous detectors. With the parameters chosen for the realization reported in this Note, it can, in principle, operate from 60 Hz up to 400 kHz. Using good quality sine input, deviations from the 90° phase lag of the quadrature output are not larger than 0.2° in the frequency range between 60 Hz and 100 kHz.