Effect of cell-phone radiation exposure on cognitive function in humans

Several papers reporting on cognitive function and exposure to cell-phone RF fields have appeared in scientific journals. Human subjects exposed to cell-phone fields showed faster responses in simple reaction time and in choice reaction time. In addition, some investigations have found exposure to cell-phone fields has a facilitating effect on tasks that require attention and manipulation of information in working memory. Also, the same group failed to confirm their earlier findings when they repeated their experiments. On the other hand, as a follow-up, different research groups examined the relationship between the reported facilitating effect and cell-phone exposure. Their results indicated that cognitive process, such as attentional function, are differentially enhanced after exposure to the RF fields emitted by cell phones.     

Cataracts and cell-phone radiation

A concern that is often expressed about microwave radiation is the induction of cataracts. The formation of lens opacities in the eyes of laboratory animals following acute microwave exposure is well established. It is generally accepted that acute exposure to higher levels of CW radiation causes various degrees of lens opacification in laboratory animals at many microwave frequencies. However, the exact conditions under which these changes may occur in human beings are a subject of debate. Nevertheless, linear extrapolations of computed results indicate that the incident density required for the human eye to reach the cataractogenic threshold may only be slightly lower than that needed for rabbits.     

基于脉冲函数电流模型对闪电回击电磁场的计算

基于一种新的描述回击通道底部电流的脉冲函数模型，利用偶极子法对距离回击通道底部不同距离处的LEMP进行了计算，把几种闪电回击的工程模型的计算结果与实测结果进行了比较，表明MTLL模型能够与实际结果更为吻合。     

Occupational exposure to radio-frequency electromagnetic fields

Occupational exposure to radio-frequency (RF) electro-magnetic (EM) fields occurs in various industrial processes. The exposure usually takes place in the near field, i.e., within one free space wavelength from the RF source. When a survey of a workplace is performed from a leakage radiation point of view, the near-field situation implies that the electric as well as the magnetic field strengths have to be monitored in order to assess the health hazard. This paper discusses the field strengths typically encountered in some of these occupational situations. Thin sheets of plastic materials can be joined or sealed by application of RF energy. The plastic welding machine, using for this purpose, usually does not have shielded electrodes and this may lead to high levels of RF fields in the immediate vicinity of the machines. The ANSI standard is exceeded in several cases near the plastic welding machines. In medicine, for instance, RF energy is used in shortwave therapy. Due to the construction of the apparatus (i.e. presence of electrodes and cables) the physiotherapist as well as the maintenance personnel may be exposed to very high levels of both E and H fields. The results of measurements of these fields in the vicinity of shortwave diathermy apparatus are discussed. The maintenance personnel working in FM/TV broadcast towers are another group of workers subject to occupational exposure of intense RF fields, and some recent studies of the exposure are presented.     

Guided quasistatic fields in electromagnetic measurement-while-drilling

The quasistatic fields of extremely low frequencies (ELF) employed to communicate from underground to the ground surface in the electromagnetic measurement-while-drilling (EM-MWD) system are investigated. Three types of well, the vertical well, directional well, and horizontal well are considered. Computed results are obtained for various parameters, including the operating frequencies and the Earth's conductivities. It is demonstrated that long drill strings have a guiding effect which is advantageous to the data transmission.<>     

Rotational symmetries of electromagnetic radiation fields

Maxwell's equations and their solutions have been examined from the point of view of the full rotation group. Two mapping theorems have been derived which give the rotational symmetries of the radiated electric and magnetic and Poynting's vector field as a function of the symmetries of the electric current density which acts as the radiating source.     

Characterisation of electromagnetic fields in buildings

Cumulative distributions of both electric and magnetic fields are given for the indoor environment in Canada. The statistics indicate that an E-field strength susceptibility limit of 3 V/m corresponding to a cumulative probability level of 95.0%, and a susceptibility limit of 5 V/m, with a cumulative probability level of 99.2%, would be adequate for the territory covered. A gamma distribution model of the data is found to be superior to a Gaussian model.<>     

Longitudinal electromagnetic fields in an aperiodic structure

The propagation of the electromagnetic wave in an aperiodic disk-loaded accelerating section has been studied using the field-matching technique. A matrix formalism similar to that of the scattering theory is applied. The method developed allows study of an arbitrary number of irises and radial space harmonics. Reflection and transmission coefficients of the structure, its wave and coupling impedances, beam loading, and other characteristics have been calculated as a function of the wave frequency. The modifications of the reflection coefficient by couplers have also been studied. The results of calculations for the detuned accelerating structure designed as SLAC for the Next Linear Collider, and consisting of over 200 cells, are given as an example     

Generalized decomposition of electromagnetic fields inbi-anisotropic media

TE/TM decomposition of electromagnetic fields, with respect to one special direction in space, is well known to be valid for fields in isotropic and uniaxially anisotropic media. The theory was recently generalized to bi-anisotropic media by defining the decomposition for linear combinations of electric and magnetic fields with respect to two vectors. In the present paper, the theory is further generalized by defining the decomposition with respect to four vectors (two six-vectors), which restrict the polarizations of the decomposed electromagnetic fields. It is shown that the class of bi-anisotropic media in which electromagnetic fields can be decomposed into two independent electromagnetic fields (a-field and b-field) is more general than in all previous decomposition theories. It is also shown that the decomposed a- and b-fields see the original bi-anisotropic medium as simpler equivalent ones (aand b-media) for which analytic Green dyadics were previously derived by these authors     

Mapping of electromagnetic fields by photochemical reaction

A standard photographic film was proved to be applicable to a quick and easy direct mapping of an electromagnetic field. The method utilises selective development of the film in accordance with the thermo-image produced by the electromagnetic field. The method would be most useful for preparing microwave holograms.     

Steady magnetic fields in noninvasive electromagnetic flowmetry

Transcutaneous electromagnetic (EM) flowmetry measures, noninvasively, the induced voltage generated by the flow of blood through a region immersed in a magnetic field. Steady magnetic fields of less than 0.5 tesla (T) have been used to measure pulsatile popliteal, brachial, and bilateral common carotid blood flow in normal subjects, in patients with arteriovascular disease, and in subjects with arteriovenous fistula (AVF) surgically created for hemodialysis. In these studies, field magnitude and time of exposure were below the limits suggested by two exposure guidelines available. Flow rate was calculated from the measured voltages and geometrical and electrical parameters using equations developed for three-media (body segment-vessel-blood) cylindrical models, based on electromagnetic theory. The 68 measurements reported here are in the expected range.     

The electromagnetic fields of elliptical torus knots

The electromagnetic radiation and scattering properties of thin perfectly conducting knotted wires are investigated. A particular class of knots, which we call elliptical torus knots, are introduced for the purposes of this investigation. These knots derive their name from the fact that they may be constructed on the surface of a virtual torus which has an elliptical cross section. The parameterizations which describe the curves of these knots are more general than any which have been considered in previous studies and, therefore, provide more flexibility in the design of knotted wire scatterers. A moment method technique is applied to model the backscattering from an elliptical trefoil knot as a function of frequency, polarization, and incidence angle     

太赫兹电波传播及信道特性

电磁暴露安全是当前5G通信在大规模商业化推广过程中需高度重视的问题。大规模多输入多输出（multiple-input multiple-output, MIMO）和天线3D波束成形等技术在现有5G基站中已得到成熟应用,但以往传统确定性方法在评估该类基站时过于保守,很难得到准确可信的基站电磁暴露评估结果。本文在以往基于蒙特卡洛（Monte Carlo,MC）统计方法的5G基站电磁暴露评估模型基础上,进一步模拟构建了城镇基站小区的三维用户场景,采用电磁暴露相对因子作为衡量指标实现了更真实用户场景下的5G基站电磁暴露水平评估。结果表明,在文中给定的两类基站配置参数下,5G基站小区在最坏情况下电磁暴露相对因子计算结果最大值仅有保守确定性方法给出的电磁暴露评估结果的25%左右,说明5G基站引入大规模MIMO和波束成形技术后不仅改善了用户通信质量,同时也使覆盖区域内电磁暴露量值分布更为均匀,得到了比传统基站更低的电磁暴露水平.

     

The uniqueness theorem of electromagnetic fields in losslessregions

The uniqueness theorem for a dissipationless medium is proved exactly. The uniqueness in multimedia regions is also discussed     

Circular TEM cell for generating standard electromagnetic fields

A circular TEM (CTEM) cell for achieving the radiated EMC test without any rotation of the equipment under test is proposed. The authors also analyse field uniformity inside the cell and characteristic impedance by using a moment method (MM) which can determine the number of segments per line efficiently     

On neutral particle trapping in quasistatic electromagnetic fields

Some basic considerations regarding the confinement of bound neutral systems of particles in limited regions of space by slowly varying electromagnetic fields are reviewed. Electrostatic traps are described, spectroscopic linewidth is discussed, and several specific cases are described briefly. Use of a light field to lengthen the trapping time of decaying states is proposed. A universal refrigeration system utilizing trapped ions is presented, and its utility for cooling neutrals as well as other charged particles is discussed.     

Numerical analysis of electromagnetic fields in biological issues

The feasibility of using integral equation techniques to predict EM fields in biological tissues is demonstrated by analyzing the scattering from arbitrary cylinders composed of lossy dielectric materials. For the circular cylinder case, good agreement is obtained between moment method solutions and exact solutions. To show the applicability to arbitrary geometries, an elliptical cylinder is also considered.