随年龄变化的生物组织介电特性的数值模拟与研究

发布时间：2018-01-17 13:12

本文关键词：随年龄变化的生物组织介电特性的数值模拟与研究　出处：《兰州交通大学》2016年硕士论文　论文类型：学位论文

【摘要】：目前已有的对青少年及婴幼儿在手机辐射等电磁暴露下的安全评估中采用的是大都是成年人的生物组织介电特性数据,这给电磁暴露评估结果带来一定的误差。由文献可知猪的生物组织介电特性与人的相似度较高,本课题以猪的生物组织测量数据为基础,分别确立幼年、青少年、成年三个年龄段人体组织的四阶Cole-Cole模型参数,设计了手机天线并进行人头在手机辐射下的电磁暴露安全评估。具体包含如下内容:(1)介绍了生物介电特性的理论研究及实验测量的研究历史。详细阐述了生物介电弛豫和色散特性、微观及宏观极化机制及描述生物介电特性的常用数学模型。(2)鉴于最小二乘法良好的拟合特性及牛顿迭代法收敛速度快的特点,采用最小二乘法与牛顿迭代法相结合的方法,对三个年龄段猪的15种组织的介电实验数据进行拟合,得到了不同年龄段四阶Cole-Cole模型拟合参数;由于猪的组织介电特性与人的相似度较高,不同年龄段猪的生物组织介电特性测量数据所确立的四阶Cole-Cole模型参数可用于预测不同年龄段人的组织介电参数;对比分析了不同年龄段组织介电特性的差异与拟合参数的差异。(3)设计了中心频率为835MHz的平面倒F天线。以经典三层球模型作为头模型,计算了三个年龄段的头部组织在同一频率下的介电参数,对手机辐射下人头的SAR值进行了计算,对比分析了计算结果。表明:三个年龄段下人头在手机辐射下的SAR值均在规定安全范围内,但随着年龄的减小,人头吸收手机电磁辐射的能量会增加。因此,儿童更应注意避免长时间暴露在电磁辐射环境中。
[Abstract]:At present, the data of dielectric properties of biological tissues, which are mostly adults, have been used in the safety assessment of adolescents and infants under electromagnetic exposures such as mobile phone radiation. According to the literature, we know that the dielectric properties of pig's biological tissue and the similarity between human and human are very high. Based on the measurement data of pig's biological tissue, we establish the infant separately. Parameters of fourth-order Cole-Cole model of human tissue in adolescents and adults of three ages. The antenna of mobile phone is designed and the electromagnetic exposure of human head under the radiation of mobile phone is evaluated. The theoretical study and experimental measurement of biological dielectric properties are introduced, and the characteristics of biological dielectric relaxation and dispersion are described in detail. The microscopic and macroscopic polarization mechanism and the mathematical model commonly used to describe the biological dielectric properties.) in view of the good fitting characteristics of the least square method and the fast convergence rate of Newton iterative method. Using the least square method and Newton iteration method, the dielectric data of 15 kinds of tissues in three age pigs were fitted. The fitting parameters of four-order Cole-Cole model with different ages were obtained. Because of the high similarity between the tissue dielectric properties of pigs and human beings. The parameters of the fourth-order Cole-Cole model established by measuring the dielectric properties of biological tissues in pigs of different ages can be used to predict the tissue dielectric parameters of people of different ages. A planar inverted F antenna with a central frequency of 835 MHz was designed and compared with the difference of dielectric properties and fitting parameters of different age groups. The classical three-layer spherical model was used as the head model. The dielectric parameters of the head tissue of three age groups were calculated at the same frequency, and the SAR value of the human head was calculated under the radiation of mobile phone. The results of comparison and analysis show that the SAR of human head under the radiation of mobile phone is within the prescribed safe range under the three age groups, but decreases with the age. The human head absorbs the cell phone electromagnetic radiation energy will increase. Therefore, children should pay more attention to avoid prolonged exposure to electromagnetic radiation environment.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：R594.8

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