Automatic Measurement System of High Resistance up to100TΩ

To solve the problems exist in the measurements high resistances in range of 1 MΩ~100 TΩ, such as low precision, poor repeatability, long time consuming and easy to be affected by the external environment, an adapted Wheatstone bridge for high resistances is described. The system uses two DC voltage sources to build a standard proportion, a pico-ammeter as the Null-indicator. The automatic balancing of the bridge is realized through the balance algorithm. The measurement software is compiled to realize the automatic measurement of high resistance. The shielding system is studied, the methods to improve the accuracy are summarized. The experimental results show that the standard uncertainty at 100GΩ reaches 3.2×10−5. The system can meet the calibration requirements of high value resistance, and has been applied in practical work.

A new automatic measurement system for high-speed railway substructure settlement based on hydrostatic pressure difference levelling

Exact settlement measurement of substructures plays an important role in their status detection throughout all-life-cycle of high-speed railway. A Hydrostatic Pressure Difference Levelling system (HPDL) is developed based on the mechanism that pressures of any two points at different elevations in incompressible static liquid are different. The approach accounts for a hyperbolic variation in the density of the pressure transmission liquid with temperature, variation in the earth’s gravitational field and the elevation at the measurement point. High accuracy capacitive differential pressure transmitters are adopted owing to their high sensitivity, temperature-insensitive, low energy consumption, and sensing stability. The HPDL results are verified with settlement values measured by the precise level. It was demonstrated that the HPDL results correlate well with the precise level and can be considered as an effective method to measure the settlement of high-speed railway substructures.

Projectile Fragmentation of 16O and 32S beams from Dubna LHE Synchrophasotron

We investigate the charge changing collisions for 16O and 32S beams, using the experimental method of Solid State Nuclear Track Detectors (SSNTD). Sample reading was performed by an automatic measurement system. We determined the total charge changing cross sections and the partial cross sections for the production of fragments of cherge 9<Z<14.