ABSTRACT
Cardiovascular disease is one of the important factors that threaten the health of residents, ranking the first among various causes of death, so the monitoring and diagnosis of human cardiovascular health is particularly important. Compared with traditional brachial artery pressure, central arterial pressure (CAP) has a higher correlation with the occurrence of many cardiovascular events. The measurement of CAP can more accurately reflect the real situation of human blood pressure, and provide an important basis for diagnosis and disease prevention. Therefore, the realization of high-precision, high-generalization ability and low-cost non-invasive measurement of CAP has always been the research focus in this field. This article combines the relevant literature in China and abroad to summarize the current status of CPA measurement, introduces related research progress from two aspects, namely parameter measurement and waveform measurement, and discusses the characteristics of the existing methods and the future development.
ABSTRACT
Abstract Introduction A ventricular assist device (VAD) is an electromechanical pump used to treat heart failures. For designing the physiological control system for a VAD, one needs a mathematical model and its related parameters. This paper presents a characterization procedure for determining the model parameter values of the electrical, mechanical, and hydraulic subsystems of a pediatric Rotary Blood Pump (pRBP). Methods An in vitro test setup consisting of a pRBP prototype, a motor driver module, an acrylic reservoir, mechanical resistance and tubings, pressure and fluid flow sensors, and data acquisition, processing, and visualization system. The proposed procedure requires a set of experimental tests, and a parameter estimation algorithm for determining the model parameters values. Results The operating limits of the pRBP were identified from the steady-state data. The relationship between the pressure head, flow rate, and the rotational speed of the pRBP was found from the static tests. For the electrical and mechanical subsystems, the dc motor model has a viscous friction coefficient that varies nonlinearly with the flow. For the hydraulic subsystem, the pressure head is assumed to be a sum of terms related to the resistance, the inertance, the friction coefficient, and the pump speed. Conclusion The proposed methodology was successfully applied to the characterization of the pRBP. The combined use of static and dynamic tests provided a precise lumped parameter model for representing the pRBP dynamics. The agreement, regarding mean squared deviation, between experimental and simulated results demonstrates the correctness and feasibility of the characterization procedure.
ABSTRACT
By the method of system identification, in this paper the mathematical models of the temperature control on fertility of the hasmaphysalis longicornis is established, and some predictions and estimations are given. The differences' between, the models and other models in the siminlar area are that,the models are coatinuous and differantiable other than segmented and undifferentiable