Research on the phase error of a Sagnac interferometer induced by modulation of a multifunctional integrated optical modulator.

High-precision IFOG requires an optical sensitivity of up to 10-8 rads-1 for interferometers; noise and error are two of the main reasons limiting its accuracy improvement. Any potential source of the signal error is worth being studied. This article introduces work on the modulation signal error caused by the mechanical vibration energy loss of MIOC crystals. This article theoretically derives and simulates the frequency spectrum of an energy loss from the perspective of electromechanical coupling and verifies it through experiments. This article also verifies the influence of MIOC mechanical loss on the output of a Sagnac interferometer through experiments. This study is an indispensable part of the bottleneck for improving the accuracy of ultrahigh-precision closed-loop IFOG and has potential engineering application value.

Cross-coupling drift between magnetic field and temperature in depolarized interferometric fiber optic gyroscope.

We propose a theory of cross-coupling drift in depolarized interferometric fiber optic gyroscopes (D-IFOGs) under the joint influence of magnetic field and temperature. The magnetic field and temperature cross-coupling drift (MTCD) originates from the interaction of the nonreciprocal circular birefringence produced by the magnetic field, the thermal stress birefringence from the varying temperature, and the inherent residual birefringence in the fiber coil. The MTCD is much greater than the sum of the individual drifts induced by magnetic field and temperature. We established a relevant theoretical model and carried out numerical simulations, and verified the results experimentally. For a typical D-IFOG, the experimental results showed a cross-coupling degree exceeding 170% when the temperature varied from -20 °C to 60 °C, as predicted in the simulations.

[Investigation of relationship between concentrated platelets and basic platelets in donors].

OBJECTIVE: To investigate the relationship between the concentrated platelets and basic platelets of donors. METHODS: We observed the harvest rate of concentrated platelets of different basic platelets in donors from Changsha area and non-Changsha area. RESULTS: The number of concentrated platelets in Group B was higher than that in Group A (P < 0.01). The harvest rates were 65.4% and 67.5% respectively in donors from Changsha area and non-Changsha area. CONCLUSION: There is positiver relationship between the harvest rate of concentrated platelets and basic platelets, and the transportation of blood does not effect the harvest rate of platelets.