Bl factor is a key system parameter of the resonant blood viscoelastic sensor. In this paper, a dynamic measurement system for the spatial distribution of Bl factor based on velocity amplitude and motional impedance was designed. The system extracted the velocity amplitude and motional impedance of the coil under the dynamic condition of driving the sensor to generate simple harmonic oscillations using laser displacement and impedance analysis combined with in-phase/quadrature demodulation algorithm, and controlled the equilibrium position of the coil by adjusting the direct current component of the excitation current to realize the position scanning. In the position interval of [−240, 240] μm, the maximum coefficient of variation of the measurement results was 0.077 3%, and the maximum relative error to the simulation results was 2.937 9%, with a linear fitting correlation coefficient R2 = 0.996 8. The system can be used to accurately measure the spatial distribution of Bl factor of the resonant blood viscoelastic sensor, which provides a technical support for the verification of the design of the sensor magnetic circuit.
In the study of embryo development process, the morphological features at different stages are essential to evaluate developmental competence of the embryo, which can be used to optimize and improve the system for in-vitro embryo culture. In this paper, an online monitoring system was designed for long-term culture of embryos, based on a monitoring strategy of low-magnification search and high-magnification observation. Three optical modules of 4× phase contrast, 10× and 20× Hoffman modulation phase contrast were configured in this system to meet the requirements of different fields of view, especially when the size of the embryo increases during the culture. Using an optomechanical system matching design, an error control and alignment test, the resolution of optical imaging was guaranteed, and a relief stereoscopic imaging with high contrast of embryos was obtained. Through low-magnification field of view to identify and locate embryos and high-magnification field of view to capture the details, the system realized online tracking and monitoring of embryos. In addition, we developed and verified an embryo identifying and locating algorithm based on image contour area and definition evaluation. The online monitoring system of in-vitro embryo culture proposed in this paper can track and record the morphological features of embryos without affecting the embryo development, providing a basis for the assessment of embryo development and the optimization of in-vitro culture system.