多层生物介质传感器的特性研究

目的多层生物介质的生物传感器被广泛应用于各大领域,其检测特性对于传感器优劣的评估尤为重要。本文目的在于量化表征多层生物介质的电学特征。方法基于生物电阻抗谱技术来探究多层生物介质的电化学阻抗谱特性,并结合保角映射的方法来量化表征多层生物介质,阐明其对阻抗的影响规律,继而为生物传感器的研制与开发提供理论基础。有效提取各生物介质层修饰后电阻抗参数(Z^(*)),从而量化表征多层生物介质层的电阻抗谱特性。结果对多层模型进行了理论计算并构建了相关试验测试系统,研究结果表明,随着生物介质层的逐步修饰,检测区域电阻抗参数(Z^(*))在f=0.1~50 MHz下持续上升,理论计算结果趋势与试验结果趋势较好吻合,论证了此理论计算方法的正确性。结论本文证实了可根据生物电阻抗谱和保角映射方法量化表征多层生物介质的电阻抗谱特性,对生物传感器的研制与开发有一定的实用价值。

基于浓厚分散系HANAI理论的血液温度生物电阻抗特性量化表征研究

温度是人体的重要机能,血液温度变化监测对人体健康评估尤为重要。本文提出拓展的浓厚分散系HANAI理论,结合生物电阻抗谱,量化表征温度对血液生物电阻抗特性的影响规律,为监测血液温度及相关血液疾病的演变过程提供基础。试验结果表明,随着温度T不断上升,血液的生物电阻抗参数Z^(+)持续下降;奈奎斯特峰值电阻参数R_(c)和峰值电抗参数X_(c)与温度T有良好的线性关系,可描述为R_(c)=-0.3T+24.14和X_(c)=0.08T-5.78。将传统HANAI方程进行拓展,并进行多物理场数值模拟,其数值分析、模拟结果与试验结果较好吻合,揭示了血浆电导率σ_(p)和细胞质电导率σ_(p)是温度对血液生物电阻抗特性的主要影响因素。本文展示了一种潜在的血液温度监测方法,在临床医学领域或有一定的科研与应用价值。

Design and Analysis of the Gemini Chain System in Dual Clutch Transmission of Automobile

Chain drive system is widely used in the conditions of high-speed, overload, variable speed and load, Many studies are focused on the meshing theory and wear characteristics of chain drive system, but system design, analysis, and noise characteristics of the chain drive system are weak. System design and noise characteristic are studied for a new type Gemini chain of dual-clutch automatic transmission. Based on the meshing theory of silent chain, the design parameters of the Gemini chain system are calculated and the mathematical models and dynamic analysis models of the Gemini chain system are established. Dynamic characteristics of the Gemini chain system is simulated and the contact force of plate and pin, plate and sprockets, the chain tension forces, the transmission error and the stress of plates and pins are analyzed. According to the simulation results of the Gemini chain system, the noise experiment about system is carried out. The noise values are tested at different speed and load and spectral characteristics are analyzed. The results of simulation and experimental show that the contact forces of plate and pin, plate and sprockets are smaller than the allowable stress values, the chain tension force is less than ultimate tension and transmission error is limited in 1.2%. The noise values can meet the requirements of industrial design, and it is proved that the design and analysis method of the Gemini chain system is scientific and feasible. The design and test system is built from analysis to test of Gemini chain system. This research presented will provide a corresponding theoretical guidance for the design and dynamic characteristics and noise characteristics of chain drive system.

基于Hadamard product优化多层神经网络的胸部电阻抗成像研究

电阻抗成像(EIT)是一种无辐射、非侵入式的可视化诊断技术。为提高胸部电阻抗成像技术重建算法的成像分辨率和去伪影能力,本研究提出了一种利用Hadamard product优化多层神经网络(MANN)的HMANN算法。将HMANN算法的重建图像与广义矢量模式匹配(GVSPM)算法、截断奇异值分解(TSVD)算法、反向传播(BP)神经网络算法和传统MANN算法的重建图像进行对比,仿真结果表明:相对于MANN算法,HMANN算法重建图像的相关系数在圆截面模型中可以提高17.30%,在肺截面模型中可以提高13.98%。虽然肺截面模型中HMANN算法重建图像的部分相关系数会有所下降,但在所有模型中,HMANN算法保留了MANN算法的图像信息,同时HMANN算法重建图像的伪影更少,检测目标与背景的可识别度比传统MANN算法高。本研究可以提升重建图像的相关系数,有效去除重建图像的伪影,为EIT成像技术提供了一种有效提升重建图像质量的新思路。