Strong Electric Field Intensity Research Articles

Possible electromagnetic interference with electronic medical equipment by radio waves coming from outside the hospital.

Electromagnetic interference (EMI) with electronic medical equipment by radio waves from mobile telephone handsets has been reported and is currently receiving wide attention. The possibility of EMI with electronic medical equipment by radio waves coming into the hospital has also been pointed out. But so far, there are no reports measuring the frequency distribution of electric field intensity induced by incoming radio waves. Therefore, we measured electric field intensity induced by radio waves coming into our 11-floor hospital, which was under construction. The maximum intensity observed was about 200 V/m at 2.79 GHz, from airport surveillance radar waves. The maximum intensity induced by radio waves from cellular phone base stations was 1.78 V/m. These data show that various frequencies of radio waves are common in this urban area, and that they induce strong electricfield intensity. This strong electric field intensity might cause EMI with electronic medical equipment. Measurement of the electromagnetic environment should be done by each hospital in urban areas to prevent EMI with electronic medical equipment.

A novel technique of electrical strengthening of soft sensitive clays by dielectrophoresis

A novel technique of electrical strengthening of soil by dielectrophoresis was developed. The process employs an alternating current at high voltage, generating a converging electric field towards the electrode by which a net resultant movement of water in the clay mass is produced towards the direction of stronger electric field intensity. Laboratory tests were developed to investigate the mechanism of this process and to explore the possibility of its application in electrical strengthening of soft sensitive clays. The preliminary results of this study showed that the process is effective, and the shear strength of the treated clay (Wallaceburg clay) increased drastically by several times with a reduction of moisture content of approximately 25% at an applied electric potential of 20 kV for 28 days. When compared with electro-osmosis, similar results are obtained in dielectrophoresis, such as the increase in preconsolidation pressure, decrease in sensitivity, and improvement of stress–strain behaviour. It is also shown that the improvement of soil properties can be greatly enhanced by increasing the applied voltage and electrode depth. Key words : dielectrophoresis, alternating current, converging electric field, high-voltage electrode, dielectric constant, electro-osmosis, soft sensitive clay, shear strength, consolidation.

Experimental Investigation on Supersonic Plasma Flow through Diverging lines of Magnetic Force

A supersonic plasma flow through the diverging lines of magnetic force is investigated experimentally. The Hall parameter of electrons is greater than unity, but that of ions is much smaller than unity. Measurements are made of the floating potential, electron temperature, ion density and ion velocity. The expansion of the plasma flow is suppressed by the external magnetic field. When the stream lines and the lines of magnetic force intersect, the electron temperature is higher at the downstream; when they are parallel to each other, a large potential difference occurs along the streamline, and equi-potential lines are crossed by the streamline. An extraordinary speed of ions is caused by the electrothermal acceleration. The strong electric field intensity along the streamlines agrees with the values estimated by the generalized Ohm's law.

Microplasmas in Alloyed Germanium P-N Junctions

Effect of dislocations present in the base crystal upon the electrical breakdown characteristics is studied for the case of germanium alloyed p+-n junctions. Microplasmas are observed at liquid nitrogen temperature. Their number seems to be approximately equal to the number of dislocations traversing the p-n boundary of the sample. Such localized breakdown is considered to be due to large saturation currents and high multiplication factor at these spots where dislocations intersect the junction. The current instability may be explained on the basis of the statistical fluctuation of the saturation currents. As to the origin of the strong electric field intensity in the vicinity of a dislocation, geometrical unevenness of the p-n boundary could be assumed. But this assumption was not successfully verified experimentally.