Numerical Simulation Of Electromagnetic Exposure Dose In Compound Field Of Rat

As the level of environmental electromagnetic radiation increases,the impact of electromagnetic radiation on health has become a topic of great concern to people.In vivo electromagnetic exposure dose is an important reference data for studying the effects of electromagnetic radiation on organisms.Determining in vivo electromagnetic exposure dose is a prerequisite for establishing a"dose-effect relationship"of electromagnetic radiation organisms.It is very important to quantitatively understand the mechanism of electromagnetic radiation affecting life.In recent decades,scholars have investigated the in vivo electromagnetic exposure dose in different electromagnetic exposure environments from the aspects of the radiation source's incident direction,polarization characteristics,frequency band characteristics,biological medium properties and the posture of exposed animals,etc.At present,these researches are mostly focused on the exposure of a single linear polarized wave,and less consideration is given to the simultaneous exposure of nonlinear polarized waves and multiple radiation sources?composite fields?.In recent years,the biological effects of electromagnetic exposure of composite fields have become a research hotspot,and the assessment of the electromagnetic exposure dose of composite fields has become an urgent problem to be solved.This article will explore this issue from the perspective of numerical dosimetry.We designed a numerical simulation system of electromagnetic exposure dose in rats based on the finite-difference time-domain method to support simultaneous irradiation of multiple wave sources.Using this system,the average body specific absorption rate?SAR_w?and tissue average specific absorption rate?SAR_a?of rats under dual-wave source incidence conditions were calculated.Different frequency combinations,combinations of incidence directions and polarization directions,and alternating incidence time intervals were discussed.The influence of other factors on SAR_w and SAR_a provides technical support for obtaining the electromagnetic exposure dose under the electromagnetic exposure conditions of the compound field.The paper mainly obtained the following research results:1.Under the condition of elliptically polarized wave incidence,the incident direction of the wave source and the ellipsometry will affect the SAR_w and SAR_a of rats,as follows:When the incident direction of the wave source is fixed,the ellipsometry will affect the SAR_w and SAR_a of rats.SAR_w fluctuates with the change of ellipsometry,and its fluctuation range is related to the incident direction of the wave source.When the wave source is incident in the direction perpendicular to the body length of the rat,its fluctuation range is limited to the SAR_w value range when the two linearly polarized waves that make up the elliptical polarized wave are incident alone?the power is the same as the elliptical polarized wave?;when the wave source When incident along the length direction of the parallel rat,its fluctuation range will exceed the SAR_w range of the two linearly polarized waves when they are incident alone.The SAR_a of different tissues in rats varies with the amplitude of ellipsometry and is affected by the direction of incidence of the wave source.The fluctuation range of SAR_a in some organizations is within the range defined by the two linearly polarized waves of ExHyKz and EyHxKz?the incident power is the same as the elliptically polarized wave?,and the fluctuation range of SAR_a in this organization will exceed this range.2.Under the compound field exposure conditions composed of two dual-wave sources with different frequencies,factors such as frequency combination,combination of incident direction and polarization direction,and alternating incidence time interval will affect SAR_w and SAR_a.The specific conclusions are as follows:Under the condition of alternating incident in the same direction,when f₁ is constant,the change law of rat SAR_w with f₂ is related to the combination of the incident direction and the polarization direction,and the combination of the incident direction and polarization direction on the SAR_w and the two components of the composite field The SAR_w of the wave source when irradiated alone is related.There is an exponential correlation between the alternating time interval period and the SAR_w value.When f₁=1.5 GHz,f₂=2.856 GHz,and the polarization direction combination is“Y-HH”?that is,both wave sources are long-axis polarization?,the electromagnetic exposure dose in the rat is the largest;when the frequency combination of the wave sources is When f₁=1.5 GHz and f₂=9.4 GHz,and the combination of polarization directions is“Y-VH”?that is,f₁ is short-axis polarization and f₂ is long-axis polarization?,the electromagnetic exposure dose in rats is the smallest.Under the condition of alternating incident in the same direction,when f₁ is constant,the SAR_a value of most tissues decreases with the increase of f₂,and the combination of the incident direction and polarization direction has different effects on the SAR_a value of different tissues.As the alternate time interval increases,the SAR_a value increases.Under the condition of vertical simultaneous incidence,the effect of the combination of frequency,incidence direction and polarization direction on SAR_w and SAR_a is similar to that under the condition of co-incidence.Under the exposure conditions considered in this paper,when f₁=1.5 GHz,f₂=2.856 GHz,and the polarization direction combination is“X-Y-HH”,the electromagnetic exposure dose in rats is the largest.Under the frequency combination of f₁=9.4 GHz and f₂=1.5 GHz,under the"X-Y-HV"irradiation conditions,the electromagnetic exposure dose in rats was the smallest.3.The SAR_w value under the exposure conditions of the dual-wave source composite field is between the SAR_w values of the two wave sources constituting the composite field when irradiated separately,but the SAR_a of some tissues and organs under certain irradiation conditions will be greater than that of the two wave sources alone.According to the organization's SAR_a.