Analysis of Electric Stress in Human Head in High-frequency Low-power Electromagnetic Environment / 生物医学工程学杂志

Action of electromagnetic radiation exerting on human body has been a concerned issue for people. Because electromagnetic waves could generate an electric stress in a discontinuous medium, we used the finite difference time domain (FDTD) as calculation methods to calculate the electric stress and its distribution in human head caused by high-frequency low-power electromagnetic environment, which was generated by dual-band (900 MHz and 1 800 MHz) PIFA antennas with radiated power 1 W, and we then performed the safety evaluation of cell phone radiation from the angle whether the electric stress further reached the human hearing threshold. The result showed that there existed the electric stress at the interface of different permittivity organization caused by the two kinds of high-frequency low-power electromagnetic environment and the maximum electric stress was located at the interface between skin and air of the phone side, and the electric stress peak at skull did not reach the threshold of auditory caused by bone tissue conduction so that it can not produce auditory effects.

A probability wave theory on the ion movement across cell membrane / 生物医学工程学杂志

The ionic quantity across the channel of the cell membrane decides the cell in a certain life state. The theory analysis that existed on the bio-effects of the electro-magnetic field (EMF) does not unveil the relationship between the EMF exerted on the cell and the ionic quantity across the cell membrane. Based on the cell construction, the existed theory analysis and the experimental results, an ionic probability wave theory is proposed in this paper to explain the biological window-effects of the electromagnetic wave. The theory regards the membrane channel as the periodic potential barrier and gives the physical view of the ion movement across cell-membrane. The theory revises the relationship between ion's energy in cell channel and the frequency exerted EMF. After the application of the concept of the wave function, the ionic probability across the cell membrane is given by the method of the quantum mechanics. The numerical results analyze the physical factors that influences the ion's movement across the cell membrane. These results show that the theory can explain the phenomenon of the biological window-effects.

A study on bio-electrochemical method for detecting environment-polluted germs / 生物医学工程学杂志

Hyperplasia of germs in biologic cell can consume certain amount of oxygen and thus will lay the foundation on which to metabolize and produce some substance. Using a Biologic cell, we have designed a kind of electric equipment for measurement which can quickly detect the environment-polluted germs, and take a sample of the environment-polluted germs in fresh milk and the microzyme in the process of beer produced. Adding proper amount of bio-coenzyme and ion-incentive to the germs liquor, we use the electric equipment to detect the sample in order to investigate the process of electron generation and germ's metabolization, including the measurement of the oxidation-reduction between the pole and the coenzyme, and the electrochemistry process of every reaction matter in the liquor. The result of our study shows that the method can effectively check the germ's number in fresh milk, and when compared to the traditional method (plate cultivating germs), it has the advantages of quickness, convenience and timeliness.

Mechanism of Biological Effects of ELF Pulsed Electromagnetic Wave on Cells / 航天医学与医学工程

Objective To observe changes of cytosolic Ca2+ levels before and after irradiation by ELF pulsed electromagnetic waves and to study the mechanism of these changes.Methods Basing on the result from experiment,time-frequency analysis was applied to analyze the bio-effects of ELF pulsed electromagnetic field on cytosolic Ca2+ levels.Results The PHMx(t,?)isoline of cytosolic Ca2+ levels of the cells before(a)and after(b)irradiation by ELF pulsed electromagnetic field was given.Electrohydrodynamic instability and a crystalline liquid biomembrane were applied to explain the mechanism of biological effects on the cells.Conclusion The cytosolic Ca2+ concentration represents a well-defined pattern of spectrum in time-frequency domain,containing continuous and dispersive spectral components.The circs which was considered to induce bio-effects in time-frequency domain presented two unique properties:the continuous spectrum of cellular Ca2+ fluctuations in time-frequency domain was narrowed by the high-energy spectrum component restrained,and the distribution and the frequencies of the dispersive spectra were changed.Furthermore,the pulse frequencies and intensities producing the bio-effects are discrete and distant.

Power density analysis on millimeter waves irradiated into cell monolayers in culture dishes / 生物医学工程学杂志

Biological effects of millimeter waves (MMWs) at the cellular level are explored in experiments using culture dishes containing cell monolayers with MMW irradiated from the underneath. Analysis is carried out for culture dishes with diameters much larger than the MMW wavelength to discover the relation between the portion of the incident MMW power density (PD) irradiated into the cell monolayer and the interfering factors such as the bottom thickness of the culture dish, the MMW wavelength, and the electromagnetic parameters of the dish and culture solution. With the help of the finite-difference time-domain (FDTD) technique, another analysis is performed to display the effect of the dish geometries upon the MMW PD irradiated into the cell monolayer in a specific culture dish with a diameter similar to the MMW wavelength. The results indicate that rigorous analysis, precise measurement and accurate calculation of MMW PD are essential accompaniments for these experiments, and large-diameter culture dishes are more preferred in experiments to small-caliber ones.