Papers by Shinji Egashira
Summary form only given. A linear antenna with a mesh reflector immersed in a plasma was studied ... more Summary form only given. A linear antenna with a mesh reflector immersed in a plasma was studied in the frequency range where electron plasma waves can propagate. The electron plasma wave appears to be difficult to excite and to be buried in the noise level because it is damped by Landau damping except in a very small region of frequency
PROCEEDINGS OF THE ITE CONVENTION PROCEEDINGS OF THE 2003 ITE ANNUAL CONVENTION, 2003
Proceedings. ICCEA 2004. 2004 3rd International Conference on Computational Electromagnetics and Its Applications, 2004., Jun 28, 2005
By equalizing the reflection coefficients, the equivalent relation between compound line and load... more By equalizing the reflection coefficients, the equivalent relation between compound line and loaded line is obtained. Using this theory shows the improvement of the linear antenna.
SPIE Proceedings, Apr 7, 2004
This paper presents the wire antenna composed of multi-step rectangular loop above the ground pla... more This paper presents the wire antenna composed of multi-step rectangular loop above the ground plane. The antenna has good characteristic when it has the surrounding length of one wavelength. We consider about theoretical composition in need of that the antenna has good characteristics and it is examined by numerical analysis and measurement whether the composition is appropriate. The antenna has high directivity in vertical plane and there is no side lobe in horizontal plane. If the antenna is composed in many side plane, it is useful as antenna for broadcasting.
We present the ladder antenna composed of multi-step rectangular loops, which are mounted on the ... more We present the ladder antenna composed of multi-step rectangular loops, which are mounted on the ground plane. The ladder antennas with two-step of square loops, rectangular loops and multi-step loops are analyzed by the moment method, and the calculated results of radiation pattern are reported. It is shown that the radiations to Z-direction from the horizontal elements add in phase and the gain of the antenna in H plane increases.
In this paper, the radiation patterns of the linear antenna by the measurement of near magnetic f... more In this paper, the radiation patterns of the linear antenna by the measurement of near magnetic field and the near electric field are estimated and compared. It is shown that the radiation patterns obtained from both measurements almost agree, except for a difference in the side lobe intensity.
PROCEEDINGS OF THE ITE CONVENTION 2002 ITE ANNUAL CONVENTION, 2002
Connective Tissue Research, 1998
The present study was carried out to investigate the relationship between the relative humidity a... more The present study was carried out to investigate the relationship between the relative humidity and the electrical resistivity of enamel in vitro. The electrical resistivity of enamel samples was measured in a thermo-hygrostat where the relative humidity varied between 60% and 90%, with the measurements carried out first in a descending direction and then in an ascending direction. When the electrical resistivity was measured from a low to high relative humidity in an ascending direction, a higher value of electrical resistivity was always obtained in comparison to that when measured in the reverse descending direction. The difference between the mean electrical resistivity in an ascending and a descending direction increased in proportion to the relative humidity. These findings suggest that the diffusion of electrolytes and water in enamel is sensitive to changes in the relative humidity.
Ergodic Theory and Dynamical Systems, Apr 1, 1997
We study a qualitative theory of compact, transversely piecewise-smooth foliated $S^1$-bundles. W... more We study a qualitative theory of compact, transversely piecewise-smooth foliated $S^1$-bundles. We show that it has the same qualitative properties as that of smooth codimension-one foliations on a compact manifold. By the obtained qualitative properties, we can deduce that the expansion growth of this foliation is classified and that the entropy of this foliation is positive if and only if there exists a resilient leaf.
Journal of The Mathematical Society of Japan, 1996
Piers Online, 2009
A novel design method for multi band antenna using different radius wires for mobile communicatio... more A novel design method for multi band antenna using different radius wires for mobile communication and Digital communications System is presented. We made a trial twoband antenna, with operating frequencies of 800 MHz and 2.1 GHz and examined the design method by comparing measured VSWR and current of the antenna and the simulation results of the antenna. We have also analyzed the trial antenna using simulation (using WIPL-D Microwave) for a different radius wires antenna mounted on a finite ground plane. The simulation results of the current and VSWR are in good agreement with the experimental results.
Proceedings of the ... ITE annual convention, Aug 27, 2001
Electronics and communications in Japan, 1982
IEEE Antennas and Propagation Society International Symposium 1992 Digest, 1992
Summary form only given. A linear antenna with a mesh reflector immersed in a plasma was studied ... more Summary form only given. A linear antenna with a mesh reflector immersed in a plasma was studied in the frequency range where electron plasma waves can propagate. The electron plasma wave appears to be difficult to excite and to be buried in the noise level because it is damped by Landau damping except in a very small region of frequency
Journal of disaster research, Jun 1, 2010
Many sediment related disasters have occurred in many areas of the world. The table of sediment r... more Many sediment related disasters have occurred in many areas of the world. The table of sediment related disasters from 1997 to 2006 is shown. It shows strong earthquakes and super hurricanes/typhoons cause large landslides and debris flows. Climate change may trigger larger disasters more frequently in the future. Stratovolcanoes are geologically weak and cause huge landslides and debris avalanches. Active volcanoes release lava flows and pyroclastic flows, which cause serious damages. As an example of a typical sediment disaster, a disaster which occurred in Venezuela, in 1999 is briefly reported. The disaster was caused by unusual heavy rainfall. Many people were killed by many debris flows and shallow landslides. The disaster shows information on hazards such as hazard maps and rainfall is necessary and control structures may reduce damages if they had existed. Proper land-use and hazard education are needed.
Chirigaku hyouron, Mar 1, 2021
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Papers by Shinji Egashira