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Objective To analyze the difference of teaching modes of course of digital signal processing for the undergraduates and postgraduates.Methods The teaching modes were compared from the aspects of educational objective,teaching content, teaching method,examination mode and etc.Results Differentiated teaching modes contributed to the satisfactory education of the undergraduates and postgraduates. Conclusion The differentiated teaching modes for the undergraduates and postgraduates provide references for the high-level education in universities and colleges of science and technology. [Chinese Medical Equipment Journal,2018,39(5):87-89,102]
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Objective To propose a method for accurately controlling the resistivity of 3D printing materials to facilitate to establish a human-head volume conductor model.Methods Two kinds of ABS/CB composite conductive printing materials covering the resistivity ranges of parenchymal and skull were selected through resistivity measurement and analysis. The correlation between the proportions and resistivities of the two kinds of ABS/CB materials and the empirical formula on the correlation between the resistivity and proportion was obtained through exponential function fitting. Results The selected ABS/CB composite material behaved well in frequency stability and time stability,and the obtained empirical formula had high-correlation coefficient.Conclusion Accurate control of 3D printing model resistivity is realized,and it's facilitated to gain 3D printing material with the same resistivity as those of skull and parenchymal.
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Objective To monitor and compare the effects of body position on the regional lung volume and FEV1/FVC with electrical impedance tomography(EIT).Methods Twelve healthy young subjects[(26.6±2.5)yr]were detected by EIT during FVC maneuver in 3 body positions (sitting,supine and prone).Functional EIT images of FVC and FEV1/FVC were obtained;the proportion of regional ventilation volume and the mean of regional FEV1/FVC were calculated.Results The ventral and dorsal proportion of ventilation volume was 37.65% : 62.35% in sitting position and 37.59% : 62.41% in supine position, respectively.While in the prone position,the value was 48.56%:51.44%,which was close to 1:1.The mean of regional FEV1/FVC in the dependent lung region was 0.84 in supine position and 0.81 in prone position,while in sitting position,the corresponding value was 0.90 and 0.94, respectively. Conclusion The results shows that the ventilation transfers to the gravity dependent region obviously, while the flow rate decreases. The result provides direct evidences for mechanical ventilation patients using prone position to improve oxygenation,as well as a research foundation for EIT monitoring regional lung ventilation in the clinical setting.
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Objective To study a method for monitoring multichannel electrode-scalp contact impedances in electrical impedance tomography (EIT), and to provide support for exploring the impact of contact impedances on imaging and the suppression method.Methods A reference electrode was introduced for the system,placed on the back of the neck or the top of the head. In the spare time of boundary voltage signal acquisition phase, the method of two electrodes was adopted to measure the electrical impedance between each imaging electrode and reference electrode, which was used to analyze the characteristics of multichannel contact impedances.Based on the existing EIT hardware system,the module for monitoring multichannel contact impedance was implemented.Results The calibration board test showed that the measurement error of this method was less than 1‰,and the maximum relative fluctuation of the measurement result within 10 hours was less than 1‰. Preliminary human test indicated that this method had the ability to obtain two kinds of information about spatial consistency and temporal stability of 16-channel contact impedances. Conclusion This method has high accuracy and stability,so it meets the requirements of monitoring multichannel contact impedances in brain EIT.